U.S. patent application number 15/725734 was filed with the patent office on 2018-04-12 for method for controlling electrical conductivity of lubricating oils in electric vehicle powertrains.
The applicant listed for this patent is ExxonMobil Research and Engineering Company. Invention is credited to James T. Carey, Samuel Flores-Torres, David G.L. Holt.
Application Number | 20180100118 15/725734 |
Document ID | / |
Family ID | 61830528 |
Filed Date | 2018-04-12 |
United States Patent
Application |
20180100118 |
Kind Code |
A1 |
Flores-Torres; Samuel ; et
al. |
April 12, 2018 |
METHOD FOR CONTROLLING ELECTRICAL CONDUCTIVITY OF LUBRICATING OILS
IN ELECTRIC VEHICLE POWERTRAINS
Abstract
This disclosure relates to a method for minimizing the
electrical drainage of charged electrical powertrain components, a
method for controlling electrical conductivity over a lifetime of a
lubricating oil in an electric vehicle powertrain lubricated with
the lubricating oil, and a method for obtaining a desired
electrical conductivity-to-dielectric constant ratio of a
lubricating oil for an electric vehicle powertrain and powertrain
components. The methods relate to controlling at least one of
oxidation, deposit formation and corrosion over the service
lifetime of the oil. The lubricating oil has a composition
including a lubricating base oil as a major component, an additive
package, as a minor component, and an effective amount of one or
more conductivity agents, as a minor component. The lubricating oil
has an electrical conductivity from 10 pS/m to 20,000 pS/m, a
dielectric constant of 1.6 to 3.6, with a ratio of electrical
conductivity-to-dielectric constant from 5 to 10,000.
Inventors: |
Flores-Torres; Samuel;
(Burlington, NJ) ; Holt; David G.L.; (Medford,
NJ) ; Carey; James T.; (Medford, NJ) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
ExxonMobil Research and Engineering Company |
Annandale |
NJ |
US |
|
|
Family ID: |
61830528 |
Appl. No.: |
15/725734 |
Filed: |
October 5, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62405285 |
Oct 7, 2016 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C10N 2040/04 20130101;
C10M 2207/144 20130101; C10M 2205/0285 20130101; C10M 2207/282
20130101; C10N 2030/00 20130101; C10N 2040/16 20130101; C10M 169/04
20130101; C10M 2207/2805 20130101; C10M 2207/125 20130101; C10M
2223/045 20130101; C10N 2030/12 20130101; C10M 2203/1025 20130101;
C10N 2010/04 20130101; C10N 2030/02 20130101; C10N 2040/02
20130101; C10N 2040/25 20130101; C10M 2203/1006 20130101; C10M
2205/223 20130101; C10N 2020/077 20200501; C10M 2205/173 20130101;
C10M 2215/224 20130101; C10M 2207/126 20130101; C10M 2215/28
20130101; C10M 2223/10 20130101; C10N 2020/02 20130101; C10M
2207/262 20130101; C10N 2060/14 20130101; C10M 2219/044 20130101;
C10M 171/02 20130101; C10M 2223/06 20130101; C10N 2030/10 20130101;
C10M 171/00 20130101; C10M 2203/1025 20130101; C10N 2020/02
20130101; C10M 2203/1025 20130101; C10N 2020/02 20130101 |
International
Class: |
C10M 169/04 20060101
C10M169/04; C10M 171/02 20060101 C10M171/02 |
Claims
1. A method for improving electrical performance in an electric
vehicle powertrain by reducing electrical charge drainage of
electrical energy storage devices and extending useful device
lifetime, said method comprising providing to an electric vehicle
powertrain a lubricating oil having a composition comprising: a
lubricating base oil as a major component; an additive package, as
a minor component comprising one or more lubricating oil additives;
and an effective amount of one or more conductivity agents, as a
minor component; wherein the lubricating oil has an electrical
conductivity from about 10 pS/m to about 20,000 pS/m, a dielectric
constant of about 1.6 to about 3.6, and a ratio of electrical
conductivity-to-dielectric constant from about 5 to less than about
1,000.
2. The method of claim 1 wherein the lubricating oil has an
electrical conductivity from about 200 pS/m to about 1,000
pS/m.
3. The method of claim 1 wherein the lubricating oil has a
dielectrical constant from about 1.8 to about 3.5.
4. The method of claim 1 wherein the lubricating oil has a
kinematic viscosity from about 2 cSt to about 20 cSt at 100.degree.
C., a total acid number (TAN) less than about 3, less than about
200 ppm active sulfur, and a viscosity index (VI) greater than
about 50.
5. The method of claim 1 wherein the lubricating oil has a
kinematic viscosity from about 2 cSt to about 14 cSt at 100.degree.
C., a total acid number (TAN) less than about 2, less than about
100 ppm active sulfur, and a viscosity index (VI) greater than
about 100.
6. The method of claim 1 wherein the lubricating base oil comprises
a Group I, Group II, Group III, Group IV, Group V base stock, or
mixtures thereof.
7. The method of claim 1 wherein the lubricating base oil
comprises: a blend of a Group IV base stock and a Group V base
stock; a blend of a Group III base stock and a Group V base stock;
a blend of a Group II base stock and a Group V base stock; or a
blend of a Group I base stock and a Group V base stock.
8. The method of claim 1 wherein the lubricating base oil
comprises: a blend of a PAO base stock and an alkylated naphthalene
or ester base stock; a blend of a GTL base stock and an alkylated
naphthalene or ester base stock; or a blend of a Group II base
stock and an alkylated naphthalene or ester base stock.
9. The method of claim 1 wherein the lubricating base oil comprises
a blend of a PAO base stock having a kinematic viscosity of about 3
cSt to about 250 cSt at 100.degree. C., and an alkylated
naphthalene or ester base stock having a kinematic viscosity of
about 2 cSt to about 22 cSt at 100.degree. C.; wherein the
lubricating oil has a kinematic viscosity from about 4 cSt to about
12 cSt at 100.degree. C.
10. The method of claim 9 wherein the PAO base oil is present in an
amount from about 5 to about 95 weight percent of the lubricating
oil, and the alkylated naphthalene or ester base oil is present in
an amount from about 5 to about 95 weight percent of the
lubricating oil.
11. The method of claim 1 wherein the lubricating base oil is
present in an amount of from about 70 weight percent to about 95
weight percent, based on the total weight of the lubricating
oil.
12. The method of claim 1 wherein the additive package is present
in an amount of from about 0.01 to about 30 percent, based on the
total weight of the lubricating oil.
13. The method of claim 1 wherein the additive package comprises
one or more lubricating oil additives selected from the group
consisting of an antioxidant; a detergent; a dispersant; an
antiwear agent; a corrosion inhibitor; a viscosity modifier; a
metal passivator; a pour point depressant; a seal compatibility
agent; an antifoam agent, an extreme pressure agent; a friction
modifier; and mixtures thereof.
14. The method of claim 1 wherein the one or more conductivity
agents are present in an amount of from about 0.01 to about 30
weight percent, based on the total weight of the lubricating
oil.
15. The method of claim 1 wherein the one or more conductivity
agents are selected from the group consisting of ionic liquids,
phospholipids, fatty acids, dispersants, detergents, antiwear
agents, polar basestock fluids, and mixtures thereof.
16. The method of claim 1 further including a dielectric agent.
17. The method of claim 16 wherein the dielectric agent comprises a
polar basestock fluid in an amount sufficient to increase the
dielectric constant by about 0.02 or more.
18. The method of claim 15 wherein the ionic liquids are present in
an amount of from about 0.01 to about 10 weight percent.
19. The method of claim 15 wherein the ionic liquid is selected
from the group consisting of 1-ethyl-3-methylimidazolium
dicyanamide, trihexyltetradecylphosphonium
bis(trifluoromethylsulfonyl)amide, trihexyl(tetradecyl)phosphonium
bis(2,4,4-trimethylpentyl)phosphinate,
tributyl(tetradecyl)phosphonium dodecylbenzenesulfonate,
1-methyl-3-butylimidazolium bis (trifluoromethanesulfonyl)imide,
and tetradecylammonium bis(2-ethylhexyl) phosphate.
20. The method of claim 15 wherein the phospholipid is
L-.alpha.-phosphatidylcholine or lecithin.
21. The method of claim 15 wherein the fatty acid is stearic
acid.
22. The method of claim 15 wherein the dispersant is selected from
the group consisting of ashless alkyl succinimides, metal-modified
alkyl succinimides, and mixtures thereof.
23. The method of claim 22 wherein the metal of the metal-modified
alkyl succinimides dispersant comprises zinc, boron, or mixtures
thereof.
24. The method of claim 15 wherein the detergent is selected from
the group consisting of metal alkyl salicylates, metal alkyl
sulfonates, calcium alkyl salicylates, calcium alkyl sulfonates,
low-base calcium alkyl salicylate, high-base calcium alkyl
salicylate, neutral calcium alkyl sulfonates, and mixtures
thereof.
25. The method of claim 15 wherein the antiwear agent is zinc
dialkyl dithiophosphate.
26. The method of claim 15 wherein the polar basestock fluid is
diethylhexyl azelate diester.
27. The method of claim 1 wherein the lubricating oil has an
operating temperature range of from about 75.degree. C. to about
110.degree. C.
28. The method of claim 1 wherein the electric vehicle powertrain
is one or more of an electric motor, an electric drive motor, a
transmission, a front axle, a rear axle, a gear box, a
differential, gears, bearings, a battery, a capacitor, a generator,
an alternator, a converter, a kinetic energy accumulator, or a
kinetic energy recovery system.
29. A method for controlling electrical conductivity over a
lifetime of a lubricating oil in an electric vehicle powertrain
lubricated with the lubricating oil, comprising providing to an
electric vehicle powertrain a lubricating oil having a composition
comprising: a lubricating base oil as a major component; an
additive package, as a minor component comprising one or more
lubricating oil additives; and an effective amount of one or more
conductivity agents, as a minor component; wherein the lubricating
oil has an electrical conductivity from about 10 pS/m to about
20,000 pS/m, a dielectric constant of about 1.6 to about 3.6, with
a ratio of electrical conductivity-to-dielectric constant from
about 5 to less than about 1,000.
30. The method of claim 29 wherein the electrical conductivity is
maintained at about 10 pS/m to about 20,000 pS/m for at least about
1,000 to about 32,000 hours.
31. The method of claim 29 wherein the electrical conductivity of
the lubricating oil is maintained at less than about 6,000 pS/m for
at least about 1,000 hours under oxidation conditions.
32. The method of claim 29 wherein the lubricating oil has an
electrical conductivity from about 200 pS/m to about 1,000
pS/m.
33. The method of claim 29 wherein the lubricating oil has a
dielectrical constant from about 1.8 to about 3.5.
34. The method of claim 29 wherein the lubricating oil has a
kinematic viscosity from about 2 cSt to about 20 cSt at 100.degree.
C., a total acid number (TAN) less than about 3, less than about
200 ppm active sulfur, and a viscosity index (VI) greater than
about 50.
35. The method of claim 29 wherein the lubricating oil has a
kinematic viscosity from about 2 cSt to about 14 cSt at 100.degree.
C., a total acid number (TAN) less than about 2, less than about
100 ppm active sulfur, and a viscosity index (VI) greater than
about 100.
36. The method of claim 29 wherein the total acid number (TAN) of
the lubricating oil is maintained at less than about 1.5 for at
least about 1,000 hours under oxidation conditions.
37. The method of claim 29 wherein the lubricating base oil
comprises a Group I, Group II, Group III, Group IV, Group V base
stock, or mixtures thereof.
38. The method of claim 29 wherein the lubricating base oil
comprises: a blend of a Group IV base stock and a Group V base
stock; a blend of a Group III base stock and a Group V base stock;
a blend of a Group II base stock and a Group V base stock; or a
blend of a Group I base stock and a Group V base stock.
39. The method of claim 29 wherein the lubricating base oil
comprises: a blend of a PAO base stock and an alkylated naphthalene
or ester base stock; a blend of a GTL base stock and an alkylated
naphthalene or ester base stock; or a blend of a Group II base
stock and an alkylated naphthalene or ester base stock.
40. The method of claim 29 wherein the lubricating base oil
comprises a blend of a PAO base stock having a kinematic viscosity
of about 3 cSt to about 250 cSt at 100.degree. C., and an alkylated
naphthalene or ester base stock having a kinematic viscosity of
about 2 cSt to about 22 cSt at 100.degree. C.; wherein the
lubricating oil has a kinematic viscosity from about 4 cSt to about
12 cSt at 100.degree. C.
41. The method of claim 40 wherein the PAO base oil is present in
an amount from about 5 to about 95 weight percent of the
lubricating oil, and the alkylated naphthalene or ester base oil is
present in an amount from about 5 to about 95 weight percent of the
lubricating oil.
42. The method of claim 29 wherein the lubricating base oil is
present in an amount of from about 70 weight percent to about 95
weight percent, based on the total weight of the lubricating
oil.
43. The method of claim 29 wherein the additive package is present
in an amount of from about 0.01 to about 30 percent, based on the
total weight of the lubricating oil.
44. The method of claim 29 wherein the additive package comprises
one or more lubricating oil additives selected from the group
consisting of an antioxidant; a detergent; a dispersant; an
antiwear agent; a corrosion inhibitor; a viscosity modifier; a
metal passivator; a pour point depressant; a seal compatibility
agent; an antifoam agent, an extreme pressure agent; a friction
modifier; and mixtures thereof.
45. The method of claim 29 wherein the one or more conductivity
agents are present in an amount of from about 0.01 to about 30
weight percent, based on the total weight of the lubricating
oil.
46. The method of claim 29 wherein the one or more conductivity
agents are selected from the group consisting of ionic liquids,
phospholipids, fatty acids, dispersants, detergents, antiwear
agents, polar basestock fluids, and mixtures thereof.
47. The method of claim 29 further including a dielectric
agent.
48. The method of claim 47 wherein the dielectric agent comprises a
polar basestock fluid in an amount sufficient to increase the
dielectric constant by about 0.02 or more.
49. The method of claim 46 wherein the ionic liquids are present in
an amount of from about 0.01 to about 10 weight percent.
50. The method of claim 46 wherein the ionic liquid is selected
from the group consisting of 1-ethyl-3-methylimidazolium
dicyanamide, trihexyltetradecylphosphonium
bis(trifluoromethylsulfonyl)amide, trihexyl(tetradecyl)phosphonium
bis(2,4,4-trimethylpentyl)phosphinate,
tributyl(tetradecyl)phosphonium dodecylbenzenesulfonate,
1-methyl-3-butylimidazolium bis (trifluoromethanesulfonyl)imide,
and tetradecylammonium bis(2-ethylhexyl) phosphate.
51. The method of claim 46 wherein the phospholipid is
L-a-phosphatidylcholine or lecithin
52. The method of claim 46 wherein the fatty acid is stearic
acid
53. The method of claim 46 wherein the dispersant is selected from
the group consisting of ashless alkyl succinimides, metal-modified
alkyl succinimides, and mixtures thereof.
54. The method of claim 53 wherein the metal of the metal-modified
alkyl succinimides dispersant comprises zinc, boron, or mixtures
thereof.
55. The method of claim 46 wherein the detergent is selected from
the group consisting of metal alkyl salicylates, metal alkyl
sulfonates, calcium alkyl salicylates, calcium alkyl sulfonates,
low-base calcium alkyl salicylate, high-base calcium alkyl
salicylate, neutral calcium alkyl sulfonates, and mixtures
thereof.
56. The method of claim 46 wherein the antiwear agent is zinc
dialkyl dithiophosphate.
57. The method of claim 46 wherein the polar basestock fluid is
diethylhexyl azelate diester.
58. The method of claim 29 wherein the lubricating oil has an
operating temperature range of from about 75.degree. C. to about
110.degree. C.
59. The method of claim 29 wherein the electric vehicle powertrain
is one or more of an electric motor, an electric drive motor, a
transmission, a front axle, a rear axle, a gear box, a
differential, gears, bearings, a battery, a capacitor, a generator,
an alternator, a converter, a kinetic energy accumulator, or a
kinetic energy recovery system.
60. The method of claim 29 wherein two or more of the lubricating
oils are used in the electric vehicle powertrain.
61. A method for lubricating an electric vehicle powertrain in an
electric vehicle by reducing electrical charge drainage of
electrical energy storage devices and extending useful device
lifetime, said method comprising providing to an electric vehicle
powertrain a lubricating oil having a composition comprising: a
lubricating base oil as a major component; an additive package, as
a minor component comprising one or more lubricating oil additives;
and an effective amount of one or more conductivity agents, as a
minor component; wherein the lubricating oil has an electrical
conductivity from about 10 pS/m to about 20,000 pS/m, a dielectric
constant of about 1.6 to about 3.6, with a ratio of electrical
conductivity-to-dielectric constant from about 5 to less than about
1,000.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to U.S. Provisional
Application Ser. No. 62/405,285 filed Oct. 7, 2016, which is herein
incorporated by reference in its entirety. This application is also
related to four copending U.S. applications, filed on even date
herewith, and identified by the following Attorney Docket numbers
and titles: 2016EM271-US2 entitled "Lubricating Oil Compositions
for Electric Vehicle Powertrains"; 2016EM273-US2 entitled "Method
for Preventing or Minimizing Electrostatic Discharge and Dielectric
Breakdown in Electric Vehicle Powertrains"; 2017EM320 entitled "Low
Conductivity Lubricating Oils For Electric And Hybrid Vehicles";
and 2017EM319 entitled "High Conductivity Lubricating Oils For
Electric And Hybrid Vehicles". Each of these co-pending US
applications is hereby incorporated by reference herein in its
entirety.
FIELD
[0002] This disclosure provides methods for controlling electrical
conductivity over a lifetime of a lubricating oil in an electric
vehicle powertrain lubricated with the lubricating oil. This
disclosure also provides methods for obtaining a desired electrical
conductivity of a lubricating oil for an electric vehicle
powertrain and powertrain components. This disclosure provides
methods for controlling electrical conductivity over a lifetime of
a lubricating oil in an electric vehicle powertrain lubricated with
the lubricating oil. This disclosure also provides methods for
obtaining a desired electrical conductivity of a lubricating oil
for an electric vehicle powertrain.
BACKGROUND
[0003] A major challenge in electric vehicle powertrain lubricant
composition is controlling lubricant electrical conductivity over
the lifetime of the lubricant. In particular, the challenge in
electric vehicle powertrain lubricant compositions is achieving
oxidation stability, deposit control, corrosion inhibition, and
lubricant compatibility with electric vehicle powertrain components
and materials over a broad temperature range.
[0004] For example, copper is present in the electric systems of
electric vehicle powertrains and requires protection at high
temperatures. Planetary gear sets, typically fabricated from
ferrous alloys and steels, are used in electric vehicle powertrains
and also require good protection. Suitable lubricant compositions,
however, may use sulfur-containing performance additives in
achieving good gear protection, but on balance, may limit sulfur
concentrations in order to achieve good copper protection.
[0005] Additionally, in electric vehicle powertrains, lubricant
electrical conductivity needs to be at the right level and
maintained over the service lifetime of the lubricating fluid. If
lubricant electrical conductivity is too low, then arcing (e.g.,
electrostatic buildup and discharge) among the electrified system
components can occur. If lubricant electrical conductivity is too
high, then the electric vehicle powertrains will adversely leak
charge.
[0006] Also, oil-derived lubricating properties must be maintained
despite exposure to high surface temperatures of electric
powertrain components. However, this lube stability must be
balanced with other lubricant properties such as low viscosity and
achieving good gear protection.
[0007] Despite advances in lubricant oil composition technology in
electric vehicles, there exists a need for an electric vehicle
powertrain lubricant composition having desired lubricant
electrical conductivity over the lifetime of the lubricant. In
particular, there is a need for electric vehicle powertrain
lubricant composition having oxidation stability, deposit control,
corrosion inhibition, and lubricant compatibility with electric
vehicle powertrain components and materials over a broad
temperature range.
SUMMARY
[0008] This disclosure relates in part to a method for preventing
or minimizing the electrical drainage of charged electrical
powertrain components, such as for example batteries, and so
improving the component energy storage lifetime, in an electric
vehicle powertrain. The method comprises controlling electrical
conductivity over a lifetime of a lubricating oil in an electric
vehicle powertrain lubricated with the lubricating oil. The method
also comprises controlling at least one of oxidation, deposit
formation and corrosion over the same lifetime of the lubricating
oil. The lubricating oil has a composition comprising a lubricating
oil base stock as a major component, and one or more lubricating
oil additives, as a minor component, and one or more conductivity
agents, as a minor component. The lubricating oil has an electrical
conductivity from about 10 pS/m to about 20,000 pS/m, a dielectric
constant of about 1.6 to about 3.6, with a ratio of electrical
conductivity-to-dielectric constant from about 5 to less than about
1,000, a kinematic viscosity from about 2 cSt to about 20 cSt at
100.degree. C., a total acid number (TAN) less than about 3, less
than about 200 ppm active sulfur, and a viscosity index (VI)
greater than about 50.
[0009] This disclosure also relates in part to a method for
controlling electrical conductivity over a lifetime of a
lubricating oil in an electric vehicle powertrain lubricated with
the lubricating oil. The method comprises controlling at least one
of oxidation, deposit formation and corrosion over the same
lifetime of the lubricating oil. The lubricating oil has a
composition comprising at least about 70 weight percent of a
lubricating oil base stock, and from about 0.01 to about 30 weight
percent of an additive package, wherein comprises one or more of
from about 0.01 to about 5 weight percent of an antioxidant, from
about 0.01 to about 10 weight percent of a detergent, from about
0.01 to about 20 weight percent of a dispersant, from about 0.01 to
about 5 weight percent of an antiwear agent, from about 0.01 to
about 5 weight percent of a corrosion inhibitor, from about 0 to
about 20 weight percent of a viscosity modifier, from about 0.01 to
about 5 weight percent of a metal passivator, and from about 0.01
to about 30 weight percent of at least one conductivity agent. Each
weight percent is based on the total weight of the lubricating oil.
The lubricating oil has an electrical conductivity from about 10
pS/m to about 20,000 pS/m, a dielectric constant of about 1.6 to
about 3.6, with a ratio of electrical conductivity-to-dielectric
constant from about 5 to less than about 1000, a kinematic
viscosity from about 2 cSt to about 20 cSt at 100.degree. C., a
total acid number (TAN) less than about 3, less than about 200 ppm
active sulfur, and a viscosity index (VI) greater than about
50.
[0010] This disclosure further relates in part to a method for
obtaining a desired electrical conductivity of a lubricating oil
for an electric vehicle powertrain. The method comprises: selecting
at least one lubricating oil base stock from a Group I, Group II,
Group III, Group IV, and Group V base oil; selecting one or more
additive package, wherein comprises one or more lubricating oil
additives from an antioxidant, a detergent, a dispersant, an
antiwear additive, a corrosion inhibitor, a viscosity modifier, a
metal passivator; selecting one or more conductivity agent;
selecting amounts of the at least one lubricating oil base stock,
the one or more additive package, and the one or more conductivity
agent; and blending the selected at least one lubricating oil base
stock, the selected at least one additive package, and the selected
one or more conductivity agent, in the selected amounts, sufficient
to obtain a desired electrical conductivity of the lubricating oil.
The lubricating oil has an electrical conductivity from about 10
pS/m to about 20,000 pS/m, a dielectric constant of about 1.6 to
about 3.6, with a ratio of electrical conductivity-to-dielectric
constant from about 5 to less than about 1,000, a kinematic
viscosity from about 2 cSt to about 20 cSt at 100.degree. C., a
total acid number (TAN) less than about 3, less than about 200 ppm
active sulfur, and a viscosity index (VI) greater than about
50.
[0011] This disclosure also relates in part to a method for
lubricating an electric vehicle powertrain. The method comprises
providing a lubricating oil, and bringing into contact the
lubricating oil with the electric vehicle powertrain. The
lubricating oil has a composition comprising a lubricating oil base
stock as a major component, and one or more lubricating oil
additives, as a minor component, and one or more conductivity
agents, as a minor component. The lubricating oil has an electrical
conductivity from about 10 pS/m to about 20,000 pS/m, a dielectric
constant of about 1.6 to about 3.6, with a ratio of electrical
conductivity-to-dielectric constant from about 5 to less than about
1,000, a kinematic viscosity from about 2 cSt to about 20 cSt at
100.degree. C., a total acid number (TAN) less than about 3, less
than about 200 ppm active sulfur, and a viscosity index (VI)
greater than about 50.
[0012] This disclosure further relates in part to a method for
lubricating an electric vehicle powertrain. The method comprises
providing a lubricating oil, and bringing into contact the
lubricating oil with the electric vehicle powertrain. The
lubricating oil has a composition comprising at least about 70
weight percent of a lubricating oil base stock, and from about 0.01
to about 30 weight percent of an additive package, wherein
comprises one or more of from about 0.01 to about 5 weight percent
of an antioxidant, from about 0.01 to about 10 weight percent of a
detergent, from about 0.01 to about 20 weight percent of a
dispersant, from about 0.01 to about 5 weight percent of an
antiwear agent, from about 0.01 to about 5 weight percent of a
corrosion inhibitor, from about 0 to about 20 weight percent of a
viscosity modifier, from about 0.01 to about 5 weight percent of a
metal passivator, and from about 0.01 to about 30 weight percent of
a conductivity agent. Each weight percent is based on the total
weight of the lubricating oil. The lubricating oil has an
electrical conductivity from about 10 pS/m to about 20,000 pS/m, a
dielectric constant of about 1.6 to about 3.6, with a ratio of
electrical conductivity-to-dielectric constant from about 5 to less
than about 1,000, a kinematic viscosity from about 2 cSt to about
20 cSt at 100.degree. C., a total acid number (TAN) less than about
3, less than about 200 ppm active sulfur, and a viscosity index
(VI) greater than about 50.
[0013] This disclosure further relates in part to an electric
vehicle comprising an electric vehicle powertrain, and a
lubricating oil which is in contact with the electric vehicle
powertrain. The lubricating oil has a composition comprising a
lubricating oil base stock as a major component, and one or more
lubricating oil additives, as a minor component, and one or more
conductivity agent, as a minor component. The lubricating oil has
an electrical conductivity from about 10 pS/m to about 20,000 pS/m,
a dielectric constant of about 1.6 to about 3.6, with a ratio of
electrical conductivity-to-dielectric constant from about 5 to less
than about 1,000, a kinematic viscosity from about 2 cSt to about
20 cSt at 100.degree. C., a total acid number (TAN) less than about
3, less than about 200 ppm active sulfur, and a viscosity index
(VI) greater than about 50.
[0014] This disclosure further relates in part to an electric
vehicle comprising an electric vehicle powertrain, and a
lubricating oil which is in contact with the electric vehicle
powertrain and powertrain components. The lubricating oil has a
composition comprising at least about 70 weight percent of a
lubricating oil base stock, from about 0.01 to about 30 weight
percent of an additive package, wherein comprises one or more of
from about 0.01 to about 5 weight percent of an antioxidant, from
about 0.01 to about 10 weight percent of a detergent, from about
0.01 to about 20 weight percent of a dispersant, from about 0.01 to
about 5 weight percent of an antiwear agent, from about 0.01 to
about 5 weight percent of a corrosion inhibitor, from about 0 to
about 20 weight percent of a viscosity modifier, from about 0.01 to
about 5 weight percent of a metal passivator, and from about 0.01
to about 30 weight percent of a conductivity agent. Each weight
percent is based on the total weight of the lubricating oil. The
lubricating oil has an electrical conductivity from about 10 pS/m
to about 20,000 pS/m, a dielectric constant of about 1.6 to about
3.6, with a ratio of electrical conductivity-to-dielectric constant
from about 5 to less than about 1,000, a kinematic viscosity from
about 2 cSt to about 20 cSt at 100.degree. C., a total acid number
(TAN) less than about 3, less than about 200 ppm active sulfur, and
a viscosity index (VI) greater than about 50.
[0015] This disclosure yet further relates in part to an electric
vehicle powertrain comprising an electric motor, a transmission,
and a lubricating oil which is in contact with the electric motor
and the transmission. The lubricating oil has a composition
comprising a lubricating oil base stock as a major component, and
one or more lubricating oil additives, as a minor component, and
one or more conductivity agents, as a minor component. The
lubricating oil has an electrical conductivity from about 10 pS/m
to about 20,000 pS/m, a dielectric constant of about 1.6 to about
3.6, with a ratio of electrical conductivity-to-dielectric constant
from about 5 to less than about 1,000, a kinematic viscosity from
about 2 cSt to about 20 cSt at 100.degree. C., a total acid number
(TAN) less than about 3, less than about 200 ppm active sulfur, and
a viscosity index (VI) greater than about 50.
[0016] This disclosure further relates in part to an electric
vehicle powertrain comprising an electric motor, a transmission,
and a lubricating oil which is in contact with the electric motor
and the transmission. The lubricating oil has a composition
comprising at least about 70 weight percent of a lubricating oil
base stock, and from about 0.01 to about 30 weight percent of an
additive package, wherein comprises one or more of from about 0.01
to about 5 weight percent of an antioxidant, from about 0.01 to
about 10 weight percent of a detergent, from about 0.01 to about 20
weight percent of a dispersant, from about 0.01 to about 5 weight
percent of an antiwear agent, from about 0.01 to about 5 weight
percent of a corrosion inhibitor, from about 0 to about 20 weight
percent of a viscosity modifier, from about 0.01 to about 5 weight
percent of a metal passivator, and from about 0.01 to about 30
weight percent of a conductivity agent. Each weight percent is
based on the total weight of the lubricating oil. The lubricating
oil has an electrical conductivity from about 10 pS/m to about
20,000 pS/m, a dielectric constant of about 1.6 to about 3.6, with
a ratio of electrical conductivity-to-dielectric constant from
about 5 to less than about 1,000, a kinematic viscosity from about
2 cSt to about 20 cSt at 100.degree. C., a total acid number (TAN)
less than about 3, less than about 200 ppm active sulfur, and a
viscosity index (VI) greater than about 50.
[0017] It has been surprisingly found that, in accordance with this
disclosure, improvement in lubricant electrical conductivity
control is obtained in an electric vehicle powertrain lubricated
with a lubricating oil, by including one or more lubricating oil
additives in the lubricating oil (e.g., antioxidant, detergent,
dispersant, antiwear agent, corrosion inhibitor, viscosity
modifier, and metal passivator). The addition of the one or more
lubricating oil additives affords greater improvements in oxidation
stability, deposit control, corrosion inhibition, and lubricant
compatibility with electric vehicle powertrain components and
materials over a broad temperature range.
[0018] Further it has been surprisingly found that, in accordance
with this disclosure, improvement in lubricant electrical
conductivity control is obtained, and at least one of oxidation
stability, deposit control, corrosion inhibition, and lubricant
compatibility with electric vehicle powertrain components and
materials over a broad temperature range, is maintained or improved
as compared to lubricant electrical conductivity control, oxidation
stability, deposit control, corrosion inhibition, and lubricant
compatibility with electric vehicle powertrain components and
materials over a broad temperature range, achieved using a
lubricating oil containing a minor component other than the one or
more lubricating oil additives. The addition of the one or more
lubricating oil additives affords greater improvements in lubricant
electrical conductivity control, while maintaining or improving at
least one of oxidation stability, deposit control, corrosion
inhibition, and lubricant compatibility with electric vehicle
powertrain components and materials over a broad temperature
range.
[0019] This disclosure relates to lubricating oils that include,
for example, oils of lubricating viscosity, working fluids, and
oil-based coolants. This disclosure also relates to the lubrication
of electric vehicles that comprise electric vehicle powertrains
that include, for example, electric vehicle powertrain systems,
electromechanical systems, kinetic energy recovery systems, or
combinations thereof. In this disclosure, electric vehicles
include, for example, all-electric vehicles, and hybrid or hybrid
electric vehicles, which may have any of a variety of parallel or
series electromechanical configurations.
[0020] Other objects and advantages of the present disclosure will
become apparent from the detailed description that follows.
DETAILED DESCRIPTION
[0021] All numerical values within the detailed description and the
claims herein are modified by "about" or "approximately" the
indicated value, and take into account experimental error and
variations that would be expected by a person having ordinary skill
in the art.
[0022] It has now been found that improved lubricant electrical
conductivity control can be attained in an electric vehicle
powertrain lubricated with a lubricating oil that has one or more
lubricating oil additives (e.g., antioxidant, detergent,
dispersant, antiwear additive, corrosion inhibitor, viscosity
modifier, and metal passivator), and one or more conductivity
agents in the lubricating oil. Conductivity agents increase the
conductivity of a lubricating or working fluid by a tangible
quantity, for example, an increment of +100 pS/m or more, when
added to such fluid in an effective amount. The lubricating oil has
a composition comprising a lubricating oil base stock as a major
component, the one or more lubricating oil additives, as a minor
component, and the one or more conductivity agents, as a minor
component. The lubricating oils of this disclosure are particularly
advantageous as passenger electric vehicle powertrain oil products.
The lubricating oils that contain one or more lubricating oil
additives are particularly useful in controlling electrical
conductivity in low viscosity electric vehicle powertrain oils. In
one aspect, the lubricating oils of this disclosure that contain
one or more lubricating oil additives are particularly useful in
controlling lubricant electrical conductivity to minimize battery
drainage and improve battery lifetime, where the ratio of
conductivity-to-dielectric constant is less than about 1,000. In
another aspect, the lubricating oils of this disclosure that
contain one or more lubricating oil additives are particularly
useful in controlling lubricant electrical conductivity to improve
bearing-related electric discharge performance, where the ratio of
conductivity-to-dielectric constant is equal to or greater than
about 1,000, and may particularly range from about 1,000 to about
10,000.
[0023] In an embodiment, lubricant electrical conductivity control
in electric vehicle powertrains is improved and at least one of
oxidation stability, deposit control, corrosion inhibition, and
lubricant compatibility with electric vehicle powertrain components
and materials over a broad temperature range, are maintained or
improved as compared to lubricant electrical conductivity control,
oxidation stability, deposit control, corrosion inhibition, and
lubricant compatibility with electric vehicle powertrain components
and materials over a broad temperature range, achieved using a
lubricating oil containing a minor component other than the one or
more lubricating oil additives.
[0024] The lubricant compositions of this disclosure provide
advantaged lubricant electrical conductivity control, including
advantaged oxidation stability, deposit control and corrosion
inhibition, performance in the lubrication of electric vehicle
powertrains which comprise, for example, one or more of drivelines,
transmissions, differentials, gears, gear trains, gear sets, gear
boxes, bearings, bushings, axles [front axle(s) and/or rear
axle(s)], turbines, compressors, pumps, hydraulic systems,
batteries, capacitors, electric motors, drive motors, generators,
AC/DC converters, alternators, transformers, kinetic energy
converters, kinetic energy recovery systems, and the like. In an
embodiment, a single lubricant composition can be used in the
electric vehicle powertrain. In another embodiment, more than one
lubricant composition can be used in the electric vehicle
powertrain, for example, one lubricant composition for the
transmission and another lubricant composition for another
powertrain component. An electric vehicle powertrain system
includes the combination of an electric vehicle powertrain (and
powertrain components) and a lubricating oil or working fluid that
are used in such service.
[0025] Yet further, the lubricant compositions of this disclosure
provide advantaged lubricant electrical conductivity control,
including advantaged oxidation stability, deposit control and
corrosion inhibition, performance under diverse lubrication regimes
of electric vehicle powertrains, that include, for example,
hydrodynamic, elastohydrodynamic, boundary, mixed lubrication,
extreme pressure regimes, and the like.
[0026] The lubricant compositions of this disclosure provide
advantaged lubricant electrical conductivity control, including
advantaged oxidation stability, deposit control and corrosion
inhibition, performance in electric vehicle powertrains under a
range of lubrication contact pressures, from 1 MPas to greater than
10 GPas, preferably greater than 10 MPas, more preferably greater
than 100 MPas, even more preferably greater than 300 MPas. Under
certain circumstances, the lubricant compositions of this
disclosure provide advantaged lubricant electrical conductivity
control, including advantaged oxidation stability, deposit control
and corrosion inhibition, performance in electric vehicle
powertrains at greater than 0.5 GPas, often at greater than 1 GPas,
sometimes greater than 2 GPas, under selected circumstances greater
than 5 GPas.
[0027] Further, the lubricant compositions of this disclosure
provide advantaged lubricant electrical conductivity control,
including advantaged oxidation stability, deposit control and
corrosion inhibition, performance on lubricated surfaces of
electric vehicle powertrains that include, for example, the
following: metals, metal alloys, non-metals, non-metal alloys,
mixed carbon-metal composites and alloys, mixed carbon-nonmetal
composites and alloys, ferrous metals, ferrous composites and
alloys, non-ferrous metals, non-ferrous composites and alloys,
titanium, titanium composites and alloys, aluminum, aluminum
composites and alloys, magnesium, magnesium composites and alloys,
ion-implanted metals and alloys, plasma modified surfaces; surface
modified materials; coatings; mono-layer, multi-layer, and gradient
layered coatings; honed surfaces; polished surfaces; etched
surfaces; textured surfaces; micro and nano structures on textured
surfaces; super-finished surfaces; diamond-like carbon (DLC), DLC
with high-hydrogen content, DLC with moderate hydrogen content, DLC
with low-hydrogen content, DLC with near-zero hydrogen content, DLC
composites, DLC-metal compositions and composites, DLC-nonmetal
compositions and composites; ceramics, ceramic oxides, ceramic
nitrides, FeN, CrN, ceramic carbides, mixed ceramic compositions,
cermets, and the like; polymers, thermoplastic polymers, engineered
polymers, polymer blends, polymer alloys, polymer composites;
materials compositions and composites containing dry lubricants,
that include, for example, graphite, carbon, molybdenum, molybdenum
disulfide, polytetrafluoroethylene, polyperfluoropropylene,
polyperfluoroalkylethers, and the like; super hydrophobic surfaces;
super hydrophilic surfaces; self-healing surfaces; surfaces derived
from 3-D printing or additive manufacturing techniques, which may
be additionally used as-manufactured, or used with post-printing
surface finishing, or used with post-printing surface coating.
[0028] Still further, the lubricant compositions of this disclosure
provide advantaged lubricant electrical conductivity control,
including advantaged oxidation stability, deposit control and
corrosion inhibition, performance in electric vehicle powertrains
with the one or more lubricating oil additives at effective
concentration ranges and at effective ratios in accordance with
this disclosure.
[0029] As used herein, electrical conductivity is determined in
accordance with ASTM D2624 (modified), using Model 1153 Digital
Conductivity Meter. Dielectric constant measurements were performed
using ASTM D924 and TEC FPP8 800. Kinematic viscosity is determined
by ASTM D445, total acid number (TAN) is determined by ASTM D974,
metals content is determined by ASTM D6376, active sulfur content
is determined by ASTM D129, viscosity index (VI) is determined by
ASTM D2270, density is determined by ASTM D4052, and specific heat
capacity is determined by ASTM D1269.
[0030] In an embodiment, the lubricating oils of this disclosure
have an electrical conductivity of greater than about 10 pS/m, of
greater than about 50 pS/m, or greater than about 100 pS/m, or
greater than about 300 pS/m, or greater than about 600 pS/m, or
greater than about 1,000 pS/m, or greater than about 2,000 pS/m, or
greater than about 3,000 pS/m, or greater than about 4,000 pS/m, or
greater than about 5,000 pS/m, or greater than about 6,000 pS/m, or
greater than about 8,000 pS/m, or greater than about 10,000 pS/m,
or greater than about 15,000 pS/m, or greater than about 20,000
pS/m. In another embodiment, the lubricating oils of this
disclosure have an electrical conductivity from about 10 pS/m to
about 20,000 pS/m, or from about 50 pS/m to about 19,000 pS/m, or
from about 100 pS/m to about 18,000 pS/m, or from about 1,000 pS/m
to about 18,000 pS/m, or from about 200 pS/m to about 17,000 pS/m,
or from about 200 pS/m to about 16,000 pS/m, or from about 400 pS/m
to about 16,000 pS/m, or from about 1,000 pS/m to about 16,000
pS/m, or from about 500 pS/m to about 15,000 pS/m, or from about
600 pS/m to about 14,000 pS/m, or from about 1,000 pS/m to about
14,000 pS/m, or from about 700 pS/m to about 13,000 pS/m, or from
about 800 pS/m to about 12,000 pS/m, or from about 1,000 pS/m to
about 12,000 pS/m, or from about 900 pS/m to about 11,000 pS/m, or
from about 1,000 pS/m to about 10,000 pS/m, or from about 1,000
pS/m to about 8,000 pS/m, or from about 1,000 pS/m to about 6,000
pS/m.
[0031] In an embodiment, the lubricating oils of this disclosure
have a dielectric constant from about 1.6 to about 3.6, or from
about 1.8 to about 3.5, or from about 2 to about 3.4, or from about
2.1 to about 3.2, or from about 2.2 to about 3, or from about 2.2
to about 2.8, or from about 2.2 to about 2.7, or from about 2.2 to
2.6, or about 2.2 to 2.5.
[0032] In an embodiment, the lubricating oils of this disclosure
have a ratio of conductivity-to-dielectric constant less than about
1,000, or less than about 900, or less than about 800, or less than
about 700, or less than about 600, or less than about 500, or less
than about 400, or less than about 300, or less than about 200, or
less than about 100, or less than about 50, or less than about 20,
or less than about 10. In another embodiment, the lubricating oils
of this disclosure have a ratio of conductivity-to-dielectric
constant from less than about 1,000 to about 5, or about 900 to
about 5, or about 800 to about 10, or about 700 to about 10, or
about 600 to about 10, or about 600 to about 20, or about 600 to
about 40, or about 600 to about 60.
[0033] In an embodiment, the lubricating oils of this disclosure
have a kinematic viscosity at 100.degree. C. from about 2 cSt to
about 20 cSt, or from about 3 cSt to about 18 cSt, or from about 3
cSt to about 14 cSt, or from about 3 cSt to about 10 cSt, or from
about 4 cSt to about 16 cSt, or from about 5 cSt to about 14 cSt,
or from about 6 cSt to about 12 cSt, or from about 8 cSt to about
12 cSt.
[0034] In an embodiment, the lubricating oils of this disclosure
have a total acid number (TAN) less than about 3, or less than
about 2.8, or less than about 2.6, or less than about 2.4, or less
than about 2.2, or less than about 2, or less than about 1.8, or
less than about 1.6, or less than about 1.4, or less than about
1.2, or less than about 1, or less than about 0.8, or less than
about 0.6, or less than about 0.4, or less than about 0.2.
[0035] In an embodiment, the lubricating oils of this disclosure
have less than about 200 ppm active sulfur, or less than about 100
ppm active sulfur, or less than about 75 ppm active sulfur, or less
than about 50 ppm active sulfur, or less than about 25 ppm active
sulfur, or less than about 10 ppm active sulfur, or no active
sulfur.
[0036] As used herein, active sulfur is the type of sulfur that
reacts with surfaces at low temperatures and is corrosive to such
surfaces, especially yellow metals (e.g., brass, bronze, copper,
and the like). Active sulfur is chemically aggressive, and with
yellow metals being softer than steel, they can begin to pit and
form spalls due to this chemical attack. Active sulfur, when in
contact with copper along with the presence of heat, forms copper
sulfide. This simple chemical reaction can have devastating
repercussions on the reliability of electric vehicle powertrains.
In extreme pressure situations, copper disulfide can be formed.
Both of these crystalline forms of copper are very hard and can
cause abrasive damage to powertrain surfaces. In contrast, inactive
sulfur only reacts with surfaces at high temperatures.
[0037] In an embodiment, the lubricating oils of this disclosure
have a viscosity index (VI) greater than about 50, or greater than
about 60, or greater than about 70, or greater than about 80, or
greater than about 90, or greater than about 100, or greater than
about 110, or greater than about 120.
[0038] In an embodiment, the lubricating oils of this disclosure
have a finished lubricant to density of greater than about 0.8
g/mL, or greater than about 0.82 g/mL, or greater than about 0.84
g/mL, or greater than about 0.86 g/mL, or greater than about 0.88
g/mL, or greater than about 0.9 g/mL, or greater than about 0.92
g/mL, or greater than about 0.94 g/mL, or greater than about 0.96
g/mL, or greater than about 0.98 g/mL, or greater than about 1.0
g/mL. In another embodiment, the lubricating oils of this
disclosure have a finished lubricant density of from about 0.8 g/mL
to about 1.2 g/mL, or from about 0.81 g/mL to about 1.0 g/mL, or
from about 0.82 g/mL to about 0.96 g/mL, or from about 0.83 g/mL to
about 0.92 g/mL, or from about 0.84 g/mL to about 0.9 g/mL.
[0039] In an embodiment, the lubricating oils of this disclosure
have a finished lube a specific heat capacity of greater than about
1.9 kJ/kg K, 2.0 kJ/kg K, or greater than about 2.1 kJ/kg K, or
greater than about 2.2 kJ/kg K, or greater than about 2.3 kJ/kg K,
or greater than about 2.4 kJ/kg K, or greater than about 2.5 kJ/kg
K, or greater than about 2.7 kJ/kg K, or greater than about 2.9
kJ/kg K, or greater than about 3.1 kJ/kg K, or greater than about
3.3 kJ/kg K, or greater than about 3.5 kJ/kg K.
[0040] In an embodiment, the lubricating oils of this disclosure
may encompass solid or semi-solid lubricants, such as for example
greases. Also, in an embodiment, the lubricating oils of this
disclosure have an operating temperature range of from about
75.degree. C. to about 110.degree. C.
[0041] Dielectric breakdown is another important property of the
lubricating oils of this disclosure. Dielectric breakdown is the
electrical stress that a lubricating oil can withstand without
breakdown. Dielectric breakdown is determined by ASTM D877. The
voltage at which breakdown occurs (i.e., a spark passing between
electrodes) is the test result. The lubricating oils of this
disclosure have dielectric breakdown properties sufficient to be
safely and efficiently used in electric vehicle powertrains.
Lubricating Oil Base Stocks and Cobase Stocks
[0042] A wide range of lubricating base oils is known in the art.
Lubricating base oils that are useful in the present disclosure are
natural oils, mineral oils and synthetic oils, and unconventional
oils (or mixtures thereof) can be used unrefined, refined, or
rerefined (the latter is also known as reclaimed or reprocessed
oil). Unrefined oils are those obtained directly from a natural or
synthetic source and used without added purification. These include
shale oil obtained directly from retorting operations, petroleum
oil obtained directly from primary distillation, and ester oil
obtained directly from an esterification process. Refined oils are
similar to the oils discussed for unrefined oils except refined
oils are subjected to one or more purification steps to improve at
least one lubricating oil property. One skilled in the art is
familiar with many purification processes. These processes include
solvent extraction, secondary distillation, acid extraction, base
extraction, filtration, and percolation. Rerefined oils are
obtained by processes analogous to refined oils but using an oil
that has been previously used as a feed stock.
[0043] Groups I, II, III, IV and V are broad base oil stock
categories developed and defined by the American Petroleum
Institute (API Publication 1509; www.API.org) to create guidelines
for lubricant base oils. Group I base stocks have a viscosity index
of between about 80 to 120 and contain greater than about 0.03%
sulfur and/or less than about 90% saturates. Group II base stocks
have a viscosity index of between about 80 to 120, and contain less
than or equal to about 0.03% sulfur and greater than or equal to
about 90% saturates. Group III stocks have a viscosity index
greater than about 120 and contain less than or equal to about
0.03% sulfur and greater than about 90% saturates. Group IV
includes polyalphaolefins (PAO). Group V base stock includes base
stocks not included in Groups I-IV. The table below summarizes
properties of each of these five groups. A base stock is typically
defined as one specifically characterized fluid of lubricating
viscosity. A base oil is typically defined as one or more base
stocks used in combination as a fluid of lubricating viscosity.
TABLE-US-00001 Base Oil Properties Saturates Sulfur Viscosity Index
Group I <90 and/or >0.03% and .gtoreq.80 and <120 Group II
.gtoreq.90 and .ltoreq.0.03% and .gtoreq.80 and <120 Group III
.gtoreq.90 and .ltoreq.0.03% and .gtoreq.120 Group IV
polyalphaolefins (PAO) Group V All other base oil stocks not
included in Groups I, II, III or IV
[0044] Natural oils include animal oils, vegetable oils (castor oil
and lard oil, for example), and mineral oils. Animal and vegetable
oils possessing favorable thermal oxidative stability can be used.
Of the natural oils, mineral oils are preferred. Mineral oils vary
widely as to their crude source, for example, as to whether they
are paraffinic, naphthenic, or mixed paraffinic-naphthenic. Oils
derived from coal or shale are also useful. Natural oils vary also
as to the method used for their production and purification, for
example, their distillation range and whether they are straight run
or cracked, hydrorefined, or solvent extracted.
[0045] Group II and/or Group III hydroprocessed or hydrocracked
base stocks, including synthetic oils such as alkyl aromatics and
synthetic esters are also well known base stock oils. High-quality
Group II and Group III hydroprocessed or hydrocracked hydrocarbon
base stocks (which may be known respectively as Group II+ and Group
III+) are also well known as useful base stock oils. For example,
ExxonMobil EHC.TM. base stocks are Group II basestocks useful in
the instant invention.
[0046] Synthetic oils include hydrocarbon oil. Hydrocarbon oils
include oils such as polymerized and interpolymerized olefins
(polybutylenes, polypropylenes, propylene isobutylene copolymers,
ethylene-olefin copolymers, and ethylene-alphaolefin copolymers,
for example). Polyalphaolefin (PAO) oil base stocks are commonly
used synthetic hydrocarbon oil. By way of example, PAOs derived
from C.sub.8, C.sub.10, C.sub.12, C.sub.14 olefins or mixtures
thereof may be utilized. See U.S. Pat. Nos. 4,956,122; 4,827,064;
and 4,827,073.
[0047] The number average molecular weights of the PAOs, which are
known materials and generally available on a major commercial scale
from suppliers such as ExxonMobil Chemical Company, Chevron
Phillips Chemical Company, BP, and others, typically vary from
about 250 to about 3,000, although PAO's may be made in viscosities
up to about 150 cSt (100.degree. C.). The PAOs are typically
comprised of relatively low molecular weight hydrogenated polymers
or oligomers of alphaolefins which include, but are not limited to,
C.sub.2 to about C.sub.32 alphaolefins with the C.sub.8 to about
C.sub.16 alphaolefins, such as 1-octene, 1-decene, 1-dodecene and
the like, being preferred. The preferred polyalphaolefins are
poly-1-octene, poly-1-decene and poly-1-dodecene and mixtures
thereof and mixed olefin-derived polyolefins. However, the dimers
of higher olefins in the range of C.sub.14 to C.sub.18 may be used
to provide low viscosity base stocks of acceptably low volatility.
Depending on the viscosity grade and the starting oligomer, the
PAOs may be predominantly trimers and tetramers of the starting
olefins, with minor amounts of the higher oligomers, having a
viscosity range of 1.5 to 12 cSt. PAO fluids of particular use may
include 3.0 cSt, 3.4 cSt, and/or 3.6 cSt and combinations thereof.
Mixtures of PAO fluids having a viscosity range of 1.5 to
approximately 150 cSt or more may be used if desired.
[0048] The PAO fluids may be conveniently made by the
polymerization of an alphaolefin in the presence of a
polymerization catalyst such as the Friedel-Crafts catalysts
including, for example, aluminum trichloride, boron trifluoride or
complexes of boron trifluoride with water, alcohols such as
ethanol, propanol or butanol, carboxylic acids or esters such as
ethyl acetate or ethyl propionate. For example the methods
disclosed by U.S. Pat. Nos. 4,149,178 or 3,382,291 may be
conveniently used herein. Other descriptions of PAO synthesis are
found in the following U.S. Pat. Nos. 3,742,082; 3,769,363;
3,876,720; 4,239,930; 4,367,352; 4,413,156; 4,434,408; 4,910,355;
4,956,122; and 5,068,487. The dimers of the C.sub.14 to C.sub.18
olefins are described in U.S. Pat. No. 4,218,330.
[0049] Other useful lubricant oil base stocks include wax isomerate
base stocks and base oils, comprising hydroisomerized waxy stocks
(e.g. waxy stocks such as gas oils, slack waxes, fuels hydrocracker
bottoms, etc.), hydroisomerized Fischer-Tropsch waxes,
Gas-to-Liquids (GTL) base stocks and base oils, and other wax
isomerate hydroisomerized base stocks and base oils, or mixtures
thereof. Fischer-Tropsch waxes, the high boiling point residues of
Fischer-Tropsch synthesis, are highly paraffinic hydrocarbons with
very low sulfur content. The hydroprocessing used for the
production of such base stocks may use an amorphous
hydrocracking/hydroisomerization catalyst, such as one of the
specialized lube hydrocracking (LHDC) catalysts or a crystalline
hydrocracking/hydroisomerization catalyst, preferably a zeolitic
catalyst. For example, one useful catalyst is ZSM-48 as described
in U.S. Pat. No. 5,075,269, the disclosure of which is incorporated
herein by reference in its entirety. Processes for making
hydrocracked/hydroisomerized distillates and
hydrocracked/hydroisomerized waxes are described, for example, in
U.S. Pat. Nos. 2,817,693; 4,975,177; 4,921,594 and 4,897,178 as
well as in British Patent Nos. 1,429,494; 1,350,257; 1,440,230 and
1,390,359. Each of the aforementioned patents is incorporated
herein in their entirety. Particularly favorable processes are
described in European Patent Application Nos. 464546 and 464547,
also incorporated herein by reference. Processes using
Fischer-Tropsch wax feeds are described in U.S. Pat. Nos. 4,594,172
and 4,943,672, the disclosures of which are incorporated herein by
reference in their entirety.
[0050] Gas-to-Liquids (GTL) base oils, Fischer-Tropsch wax derived
base oils, and other wax-derived hydroisomerized (wax isomerate)
base oils be advantageously used in the instant disclosure, and may
have useful kinematic viscosities at 100.degree. C. of about 3 cSt
to about 50 cSt, preferably about 3 cSt to about 30 cSt, more
preferably about 3.5 cSt to about 25 cSt, as exemplified by GTL 4
with kinematic viscosity of about 4.0 cSt at 100.degree. C. and a
viscosity index of about 141. These Gas-to-Liquids (GTL) base oils,
Fischer-Tropsch wax derived base oils, and other wax-derived
hydroisomerized base oils may have useful pour points of about
-20.degree. C. or lower, and under some conditions may have
advantageous pour points of about -25.degree. C. or lower, with
useful pour points of about -30.degree. C. to about -40.degree. C.
or lower. Useful compositions of Gas-to-Liquids (GTL) base oils,
Fischer-Tropsch wax derived base oils, and wax-derived
hydroisomerized base oils are recited in U.S. Pat. Nos. 6,080,301;
6,090,989, and 6,165,949 for example, and are incorporated herein
in their entirety by reference.
[0051] The hydrocarbyl aromatics can be used as a base oil or base
oil component and can be any hydrocarbyl molecule that contains at
least about 5% of its weight derived from an aromatic moiety such
as a benzenoid moiety or naphthenoid moiety, or their derivatives.
These hydrocarbyl aromatics include alkyl benzenes, alkyl
naphthalenes, alkyl diphenyl oxides, alkyl naphthols, alkyl
diphenyl sulfides, alkylated bis-phenol A, alkylated thiodiphenol,
and the like. The aromatic can be mono-alkylated, dialkylated,
polyalkylated, and the like. The aromatic can be mono- or
poly-functionalized. The hydrocarbyl groups can also be comprised
of mixtures of alkyl groups, alkenyl groups, alkynyl, cycloalkyl
groups, cycloalkenyl groups and other related hydrocarbyl groups.
The hydrocarbyl groups can range from about C.sub.6 up to about
C.sub.60 with a range of about C.sub.8 to about C.sub.20 often
being preferred. A mixture of hydrocarbyl groups is often
preferred, and up to about three such substituents may be present.
The hydrocarbyl group can optionally contain sulfur, oxygen, and/or
nitrogen containing substituents. The aromatic group can also be
derived from natural (petroleum) sources, provided at least about
5% of the molecule is comprised of an above-type aromatic moiety.
Viscosities at 100.degree. C. of approximately 3 cSt to about 50
cSt are preferred, with viscosities of approximately 3.4 cSt to
about 20 cSt often being more preferred for the hydrocarbyl
aromatic component. In one embodiment, an alkyl naphthalene where
the alkyl group is primarily comprised of 1-hexadecene is used.
Other alkylates of aromatics can be advantageously used.
Naphthalene or methyl naphthalene, for example, can be alkylated
with olefins such as octene, decene, dodecene, tetradecene or
higher, mixtures of similar olefins, and the like. Useful
concentrations of hydrocarbyl aromatic in a lubricant oil
composition can be about 2% to about 25%, preferably about 4% to
about 20%, and more preferably about 4% to about 15%, depending on
the application.
[0052] Alkylated aromatics such as the hydrocarbyl aromatics of the
present disclosure may be produced by well-known Friedel-Crafts
alkylation of aromatic compounds. See Friedel-Crafts and Related
Reactions, Olah, G. A. (ed.), Inter-science Publishers, New York,
1963. For example, an aromatic compound, such as benzene or
naphthalene, is alkylated by an olefin, alkyl halide or alcohol in
the presence of a Friedel-Crafts catalyst. See Friedel-Crafts and
Related Reactions, Vol. 2, part 1, chapters 14, 17, and 18, See
Olah, G. A. (ed.), Inter-science Publishers, New York, 1964. Many
homogeneous or heterogeneous, solid catalysts are known to one
skilled in the art. The choice of catalyst depends on the
reactivity of the starting materials and product quality
requirements. For example, strong acids such as AlCl.sub.3,
BF.sub.3, or HF may be used. In some cases, milder catalysts such
as FeCl.sub.3 or SnCl.sub.4 are preferred. Newer alkylation
technology uses zeolites or solid super acids.
[0053] Esters comprise a useful base stock. Additive solvency and
seal compatibility characteristics may be secured by the use of
esters such as the esters of dibasic acids with monoalkanols and
the polyol esters of monocarboxylic acids. Esters of the former
type include, for example, the esters of dicarboxylic acids such as
phthalic acid, succinic acid, alkyl succinic acid, alkenyl succinic
acid, maleic acid, azelaic acid, suberic acid, sebacic acid,
fumaric acid, adipic acid, linoleic acid dimer, malonic acid, alkyl
malonic acid, alkenyl malonic acid, etc., with a variety of
alcohols such as butyl alcohol, hexyl alcohol, dodecyl alcohol,
2-ethylhexyl alcohol, etc. Specific examples of these types of
esters include dibutyl adipate, di(2-ethylhexyl) sebacate,
di-n-hexyl fumarate, dioctyl sebacate, diisooctyl azelate,
diisodecyl azelate, di(2-ethylhexyl) azelate, dioctyl phthalate,
didecyl phthalate, dieicosyl sebacate, etc.
[0054] Particularly useful synthetic esters are those which are
obtained by reacting one or more polyhydric alcohols, preferably
the hindered polyols (such as the neopentyl polyols, e.g.,
neopentyl glycol, trimethylol ethane,
2-methyl-2-propyl-1,3-propanediol, trimethylol propane,
pentaerythritol and dipentaerythritol) with alkanoic acids
containing at least about 4 carbon atoms, preferably C.sub.5 to
C.sub.30 acids such as saturated straight chain fatty acids
including caprylic acid, capric acid, lauric acid, myristic acid,
palmitic acid, stearic acid, arachic acid, and behenic acid, or the
corresponding branched chain fatty acids or unsaturated fatty acids
such as oleic acid, or mixtures of any of these materials.
[0055] Suitable synthetic ester components include the esters of
trimethylol propane, trimethylol butane, trimethylol ethane,
pentaerythritol and/or dipentaerythritol with one or more
monocarboxylic acids containing from about 5 to about 10 carbon
atoms. These esters are widely available commercially, for example,
the Mobil P-41 and P-51 esters of ExxonMobil Chemical Company.
[0056] Also useful are esters derived from renewable material such
as coconut, palm, rapeseed, soy, sunflower and the like. These
esters may be monoesters, di-esters, polyol esters, complex esters,
or mixtures thereof. These esters are widely available
commercially, for example, the Mobil P-51 ester of ExxonMobil
Chemical Company.
[0057] Engine oil compositions containing renewable esters are
included in this disclosure. For such compositions, the renewable
content of the ester is typically greater than about 70 weight
percent, preferably more than about 80 weight percent and most
preferably more than about 90 weight percent.
[0058] Other useful fluids of lubricating viscosity include
non-conventional or unconventional base stocks that have been
processed, preferably catalytically, or synthesized to provide high
performance lubrication characteristics.
[0059] Useful base stock fluids also include polyethers,
polyglycols, polyalkylene glycols (PAG), polypropanols,
polyalkylene propanols, polypropylene oxides, polybutylene oxides,
to polytetrahydrofurans, polyalkylene tetrahydrofurans, and
analogues of polyether-type fluids, where such polyethers may be
uncapped, mono-capped, di-capped, or multi-capped, with functional
groups which may include for example ethers, esters, ketones,
urethanes, aromatics, heteroaromatics, hydrocarbyl moieties, etc.
In addition, useful polyether-type base stock fluids include
oil-soluble or hydrocarbon-soluble versions of polyethers or PAGs
or polyalkylene ethers or polyalkylene oxides.
[0060] Non-conventional or unconventional base stocks/base oils
include one or more of a mixture of base stock(s) derived from one
or more Gas-to-Liquids (GTL) materials, as well as
isomerate/isodewaxate base stock(s) derived from natural wax or
waxy feeds, mineral and or non-mineral oil waxy feed stocks such as
slack waxes, natural waxes, and waxy stocks such as gas oils, waxy
fuels hydrocracker bottoms, waxy raffinate, hydrocrackate, thermal
crackates, or other mineral, mineral oil, or even non-petroleum oil
derived waxy materials such as waxy materials received from coal
liquefaction or shale oil, and mixtures of such base stocks.
[0061] GTL materials are materials that are derived via one or more
synthesis, combination, transformation, rearrangement, and/or
degradation/deconstructive processes from gaseous carbon-containing
compounds, hydrogen-containing compounds and/or elements as feed
stocks such as hydrogen, carbon dioxide, carbon monoxide, water,
methane, ethane, ethylene, acetylene, propane, propylene, propyne,
butane, butylenes, and butynes. GTL base stocks and/or base oils
are GTL materials of lubricating viscosity that are generally
derived from hydrocarbons; for example, waxy synthesized
hydrocarbons, that are themselves derived from simpler gaseous
carbon-containing compounds, hydrogen-containing compounds and/or
elements as feed stocks. GTL base stock(s) and/or base oil(s)
include oils boiling in the lube oil boiling range (1)
separated/fractionated from synthesized GTL materials such as, for
example, by distillation and subsequently subjected to a final wax
processing step which involves either or both of a catalytic
dewaxing process, or a solvent dewaxing process, to produce lube
oils of reduced/low pour point; (2) synthesized wax isomerates,
comprising, for example, hydrodewaxed or hydroisomerized cat and/or
solvent dewaxed synthesized wax or waxy hydrocarbons; (3)
hydrodewaxed or hydroisomerized cat and/or solvent dewaxed
Fischer-Tropsch (F-T) material (i.e., hydrocarbons, waxy
hydrocarbons, waxes and possible analogous oxygenates); preferably
hydrodewaxed or hydroisomerized/followed by cat and/or solvent
dewaxing dewaxed F-T waxy hydrocarbons, or hydrodewaxed or
hydroisomerized/followed by cat (or solvent) dewaxing dewaxed, F-T
waxes, or mixtures thereof.
[0062] GTL base stock(s) and/or base oil(s) derived from GTL
materials, especially, hydrodewaxed or hydroisomerized/followed by
cat and/or solvent dewaxed wax or waxy feed, preferably F-T
material derived base stock(s) and/or base oil(s), are
characterized typically as having kinematic viscosities at
100.degree. C. of from about 2 mm.sup.2/s to about 50 mm.sup.2/s
(ASTM D445). They are further characterized typically as having
pour points of -5.degree. C. to about -40.degree. C. or lower (ASTM
D97). They are also characterized typically as having viscosity
indices of about 80 to about 140 or greater (ASTM D2270).
[0063] In addition, the GTL base stock(s) and/or base oil(s) are
typically highly paraffinic (>90% saturates), and may contain
mixtures of monocycloparaffins and multicycloparaffins in
combination with non-cyclic isoparaffins. The ratio of the
naphthenic (i.e., cycloparaffin) content in such combinations
varies with the catalyst and temperature used. Further, GTL base
stock(s) and/or base oil(s) typically have very low sulfur and
nitrogen content, generally containing less than about 10 ppm, and
more typically less than about 5 ppm of each of these elements. The
sulfur and nitrogen content of GTL base stock(s) and/or base oil(s)
obtained from F-T material, especially F-T wax, is essentially nil.
In addition, the absence of phosphorous and aromatics make this
materially especially suitable for the formulating of low SAP
products.
[0064] The term GTL base stock and/or base oil and/or wax isomerate
base stock and/or base oil is to be understood as embracing
individual fractions of such materials of wide viscosity range as
recovered in the production process, mixtures of two or more of
such fractions, as well as mixtures of one or two or more low
viscosity fractions with one, two or more higher viscosity
fractions to produce a blend wherein the blend exhibits a target
kinematic viscosity.
[0065] The GTL material, from which the GTL base stock(s) and/or
base oil(s) is/are derived is preferably an F-T material (i.e.,
hydrocarbons, waxy hydrocarbons, wax).
[0066] Base oils for use in the lubricating oils useful in the
present disclosure are any of the variety of oils corresponding to
API Group I, Group II, Group III, Group IV, and Group V oils, and
mixtures thereof, preferably API Group II, Group III, Group IV, and
Group V oils, and mixtures thereof, more preferably Group III,
Group IV, and Group V base oils, and mixtures thereof. Highly
paraffinic base oils can be used to advantage in the lubricating
oils useful in the present disclosure. Minor quantities of Group I
stock, such as the amount used to dilute additives for blending
into lube oil products, can also be used. Even in regard to the
Group II stocks, it is preferred that the Group II stock be in the
higher quality range associated with that stock, i.e. a Group II
stock having a viscosity index in the range 100<VI<120.
[0067] The base oil constitutes the major component of the engine
oil lubricant composition of the present disclosure and typically
is present in an amount ranging from about 50 to about 99 weight
percent, preferably from about 70 to about 95 weight percent, and
more preferably from about 85 to about 95 weight percent, based on
the total weight of the composition. The base oil may be selected
from any of the synthetic or natural oils typically used as
crankcase lubricating oils for spark-ignited and
compression-ignited engines. The base oil conveniently has a
kinematic viscosity, according to ASTM standards, of about 2.5 cSt
to about 12 cSt (or mm.sup.2/s) at 100.degree. C. and preferably of
about 2.5 cSt to about 9 cSt (or mm.sup.2/s) at 100.degree. C.
Mixtures of synthetic and natural base oils may be used if desired.
Bi-modal mixtures of Group I, II, III, IV, and/or V base stocks may
be used if desired.
Antioxidants
[0068] The lubricating oil compositions include at least one
antioxidant. Antioxidants retard the oxidative degradation of base
oils during service. Such degradation may result in deposits on
metal surfaces, the presence of sludge, or a viscosity increase in
the lubricant. One skilled in the art knows a wide variety of
oxidation inhibitors that are useful in lubricating oil
compositions. See, Klamann in Lubricants and Related Products, op
cite, and U.S. Pat. Nos. 4,798,684 and 5,084,197, for example.
[0069] Illustrative antioxidants include sterically hindered alkyl
phenols such as 2,6-di-tert-butylphenol, 2,6-di-tert-butyl-p-cresol
and 2,6-di-tert-butyl-4-(2-octyl-3-propanoic) phenol;
N,N-di(alkylphenyl) amines; and alkylated phenylenediamines.
[0070] The antioxidant may be a hindered phenolic antioxidant such
as butylated hydroxytoluene, suitably present in an amount of 0.01
to 5%, preferably 0.4 to 0.8%, by weight of the lubricant
composition. Alternatively, or in addition, the antioxidant may
comprise an aromatic amine antioxidant such as
mono-octylphenylalphanapthyl amine or p,p-dioctyldiphenylamine,
used singly or in admixture. The amine antioxidant component is
suitably present in a range of from 0.01 to 5% by weight of the
lubricant composition, more preferably 0.5 to 1.5%.
[0071] Useful antioxidants include hindered phenols. These phenolic
antioxidants may be ashless (metal-free) phenolic compounds or
neutral or basic metal salts of certain phenolic compounds. Typical
phenolic antioxidant compounds are the hindered phenolics which are
the ones which contain a sterically hindered hydroxyl group, and
these include those derivatives of dihydroxy aryl compounds in
which the hydroxyl groups are in the o- or p-position to each
other. Typical phenolic antioxidants include the hindered phenols
substituted with C.sub.6+ alkyl groups and the alkylene coupled
derivatives of these hindered phenols. Examples of phenolic
materials of this type 2-t-butyl-4-heptyl phenol; 2-t-butyl-4-octyl
phenol; 2-t-butyl-4-dodecyl phenol; 2,6-di-t-butyl-4-heptyl phenol;
2,6-di-t-butyl-4-dodecyl phenol; 2-methyl-6-t-butyl-4-heptyl
phenol; and 2-methyl-6-t-butyl-4-dodecyl phenol. Other useful
hindered mono-phenolic antioxidants may include for example
hindered 2,6-di-alkyl-phenolic proprionic ester derivatives.
Bis-phenolic antioxidants may also be advantageously used in
combination with the instant disclosure. Examples of ortho-coupled
phenols include: 2,2'-bis(4-heptyl-6-t-butyl-phenol);
2,2'-bis(4-octyl-6-t-butyl-phenol); and
2,2'-bis(4-dodecyl-6-t-butyl-phenol). Para-coupled bisphenols
include for example 4,4'-bis(2,6-di-t-butyl phenol) and
4,4'-methylene-bis(2,6-di-t-butyl phenol).
[0072] Other illustrative phenolic antioxidants include sulfurized
and non-sulfurized phenolic antioxidants. The terms "phenolic type"
or "phenolic antioxidant" used herein includes compounds having one
or more than one hydroxyl group bound to an aromatic ring which may
itself be mononuclear, e.g., benzyl, or poly-nuclear, e.g.,
naphthyl and Spiro aromatic compounds. Thus "phenol type" includes
phenol per se, catechol, resorcinol, hydroquinone, naphthol, etc.,
as well as alkyl or alkenyl and sulfurized alkyl or alkenyl
derivatives thereof, and bisphenol type compounds including such
bi-phenol compounds linked by alkylene bridges sulfuric bridges or
oxygen bridges. Alkyl phenols include mono- and poly-alkyl or
alkenyl phenols, the alkyl or alkenyl group containing from 3-100
carbons, preferably 4 to 50 carbons and sulfurized derivatives
thereof, the number of alkyl or alkenyl groups present in the
aromatic ring ranging from 1 to up to the available unsatisfied
valences of the aromatic ring remaining after counting the number
of hydroxyl groups bound to the aromatic ring.
[0073] Generally, therefore, the phenolic antioxidant may be
represented by the general formula:
(R).sub.x--Ar--(OH).sub.y
where Ar is selected from the group consisting of:
##STR00001##
wherein R is a C.sub.3-C.sub.100 alkyl or alkenyl group, a sulfur
substituted alkyl or alkenyl group, preferably a C.sub.4-C.sub.50
alkyl or alkenyl group or sulfur substituted alkyl or alkenyl
group, more preferably C.sub.3-C.sub.100 alkyl or sulfur
substituted alkyl group, most preferably a C.sub.4-C.sub.50 alkyl
group, R.sup.g is a C.sub.1-C.sub.100 alkylene or sulfur
substituted alkylene group, preferably a C.sub.2-C.sub.50 alkylene
or sulfur substituted alkylene group, more preferably a
C.sub.2-C.sub.20 alkylene or sulfur substituted alkylene group, y
is at least 1 to up to the available valences of Ar, x ranges from
0 to up to the available valances of Ar-y, z ranges from 1 to 10, n
ranges from 0 to 20, and m is 0 to 4 and p is 0 or 1, preferably y
ranges from 1 to 3, x ranges from 0 to 3, z ranges from 1 to 4 and
n ranges from 0 to 5, and p is 0.
[0074] Preferred phenolic antioxidant compounds are the hindered
phenolics and phenolic esters which contain a sterically hindered
hydroxyl group, and these include those derivatives of dihydroxy
aryl compounds in which the hydroxyl groups are in the o- or
p-position to each other. Typical phenolic antioxidants include the
hindered phenols substituted with C.sub.1+ alkyl groups and the
alkylene coupled derivatives of these hindered phenols. Examples of
phenolic materials of this type 2-t-butyl-4-heptyl phenol;
2-t-butyl-4-octyl phenol; 2-t-butyl-4-dodecyl phenol;
2,6-di-t-butyl-4-heptyl phenol; 2,6-di-t-butyl-4-dodecyl phenol;
2-methyl-6-t-butyl-4-heptyl phenol; 2-methyl-6-t-butyl-4-dodecyl
phenol; 2,6-di-t-butyl-4 methyl phenol; 2,6-di-t-butyl-4-ethyl
phenol; and 2,6-di-t-butyl 4 alkoxy phenol; and
##STR00002##
[0075] Phenolic type antioxidants are well known in the lubricating
industry and commercial examples such as Ethanox.TM. 1710,
Irganox.TM. 1076, Irganox.TM. L1035, Irganox.TM. 1010, Irganox.TM.
L109, Irganox.TM. L118, Irganox.TM. L135 and the like are familiar
to those skilled in the art. The above is presented only by way of
exemplification, not limitation on the type of phenolic
antioxidants which can be used.
[0076] Other examples of phenol-based antioxidants include
2-t-butylphenol, 2-t-butyl-4-methylphenol,
2-t-butyl-5-methylphenol, 2,4-di-t-butylphenol,
2,4-dimethyl-6-t-butylphenol, 2-t-butyl-4-methoxyphenol,
3-t-butyl-4-methoxyphenol, 2,5-di-t-butylhydroquinone (manufactured
by the Kawaguchi Kagaku Co. under trade designation "Antage DBH"),
2,6-di-t-butylphenol and 2,6-di-t-butyl-4-alkylphenols such as
2,6-di-t-butyl-4-methylphenol and 2,6-di-t-butyl-4-ethylphenol;
2,6-di-t-butyl-4-alkoxyphenols such as
2,6-di-t-butyl-4-methoxyphenol and 2,6-di-t-butyl-4-ethoxyphenol,
3,5-di-t-butyl-4-hydroxybenzylmercaptoocty-1 acetate,
alkyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionates such as
n-octyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate (manufactured
by the Yoshitomi Seiyaku Co. under the trade designation "Yonox
SS"), n-dodecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate and
2'-ethylhexyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate;
2,6-di-t-butyl-alpha-dimethylamino-p-cresol,
2,2'-methylenebis(4-alkyl-6-t-butylphenol) compounds such as
2,2'-methylenebis(4-methyl-6-t-butylphe-nol) (manufactured by the
Kawaguchi Kagaku Co. under the trade designation "Antage W-400")
and 2,2'-methylenebis(4-ethyl-6-t-butylphenol) (manufactured by the
Kawaguchi Kagaku Co. under the trade designation "Antage W-500");
bisphenols such as 4,4'-butylidenebis(3-methyl-6-t-butyl-phenol)
(manufactured by the Kawaguchi Kagaku Co. under the trade
designation "Antage W-300"),
4,4'-methylenebis(2,6-di-t-butylphenol) (manufactured by Laporte
Performance Chemicals under the trade designation "Ionox 220AH"),
4,4'-bis(2,6-di-t-butylphenol), 2,2-(di-p-hydroxyphenyl)propane
(Bisphenol A), 2,2-bis(3,5-di-t-butyl-4-hydroxyphenyl)propane,
4,4'-cyclohexylidenebis(2,6-di-t-butylphenol), hexamethylene glycol
bis[3, (3,5-di-t-butyl-4-hydroxyphenyl)propionate] (manufactured by
the Ciba Speciality Chemicals Co. under the trade designation
"Irganox L109"), triethylene glycol
bis[3-(3-t-butyl-4-hydroxy-y-5-methylphenyl)propionate]
(manufactured by the Yoshitomi Seiyaku Co. under the trade
designation "Tominox 917"),
2,2'-thio[diethyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate]
(manufactured by the Ciba Speciality Chemicals Co. under the trade
designation "Irganox L115"),
3,9-bis{1,1-dimethyl-2-[3-(3-t-butyl-4-hydroxy-5-methylphenyl)-propionylo-
xy]ethyl}2,4,8,10-tetraoxaspiro[5,5]undecane (manufactured by the
Sumitomo Kagaku Co. under the trade designation "Sumilizer GA80")
and 4,4'-thiobis(3-methyl-6-t-butylphenol) (manufactured by the
Kawaguchi Kagaku Co. under the trade designation "Antage RC"),
2,2'-thiobis(4,6-di-t-butylresorcinol); polyphenols such as
tetrakis[methylene-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionato[methane
(manufactured by the Ciba Speciality Chemicals Co. under the trade
designation "Irganox L101"),
1,1,3-tris(2-methyl-4-hydroxy-5-t-butylpheny-1)butane (manufactured
by the Yoshitomi Seiyaku Co. under the trade designation "Yoshinox
930"),
1,3,5-trimethyl-2,4,6-tris(3,5-di-t-butyl-4-hydroxybenzyl)benzene
(manufactured by Ciba Speciality Chemicals under the trade
designation "Irganox 330"),
bis[3,3'-bis(4'-hydroxy-3'-t-butylpheny-1)butyric acid] glycol
ester,
2-(3',5'-di-t-butyl-4-hydroxyphenyl)-methyl-4-(2'',4''-di-t-butyl-3''-hyd-
-roxyphenyl)methyl-6-t-butylphenol and
2,6-bis(2'-hydroxy-3'-t-butyl-5'-methylbenzyl)-4-methylphenol; and
phenol/aldehyde condensates such as the condensates of
p-t-butylphenol and formaldehyde and the condensates of
p-t-butylphenol and acetaldehyde.
[0077] Effective amounts of one or more catalytic antioxidants may
also be used. The catalytic antioxidants comprise an effective
amount of a) one or more oil soluble polymetal organic compounds;
and, effective amounts of b) one or more substituted
N,N'-diaryl-o-phenylenediamine compounds or c) one or more hindered
phenol compounds; or a combination of both b) and c). Catalytic
antioxidants are more fully described in U.S. Pat. No. 8,048,833,
herein incorporated by reference in its entirety.
[0078] Illustrative aromatic amine antioxidants include
phenyl-alpha-naphthyl amine which is described by the following
molecular structure:
##STR00003##
wherein R.sup.z is hydrogen or a C.sub.1 to C.sub.14 linear or
C.sub.3 to C.sub.14 branched alkyl group, preferably C.sub.1 to
C.sub.10 linear or C.sub.3 to C.sub.10 branched alkyl group, more
preferably linear or branched C.sub.6 to C.sub.8 and n is an
integer ranging from 1 to 5 preferably 1. A particular example is
Irganox L06.
[0079] Other aromatic amine antioxidants include other alkylated
and non-alkylated aromatic amines such as aromatic monoamines.
[0080] Typical aromatic amines antioxidants have alkyl substituent
groups of at least 6 carbon atoms. Examples of aliphatic groups
include hexyl, heptyl, octyl, nonyl, and decyl. Generally, the
aliphatic groups will not contain more than 14 carbon atoms. The
general types of such other additional amine antioxidants which may
be present include diphenylamines, phenothiazines, imidodibenzyls
and diphenyl phenylene diamines. Mixtures of two or more of such
other additional aromatic amines may also be present. Polymeric
amine antioxidants can also be used.
[0081] The antioxidants or oxidation inhibitors that are useful in
lubricant oil compositions of the disclosure are the hindered
phenols (e.g., 2,6-di-(t-butyl)phenol); aromatic amines (e.g.,
alkylated diphenyl amines); alkyl polysulfides; selenides; borates
(e.g., epoxide/boric acid reaction products); phosphorodithioic
acids, esters and/or salts; and the dithiocarbamate (e.g., zinc
dithiocarbamates). In an embodiment, these antioxidants or
oxidation inhibitors can be employed at ratios of amine/phenolic
from 1:10 to 10:1 of the mixtures preferred.
[0082] The antioxidants or oxidation inhibitors that are also
useful in lubricant oil compositions of the disclosure are
chlorinated aliphatic hydrocarbons such as chlorinated wax; organic
sulfides and polysulfides such as benzyl disulfide,
bis(chlorobenzyl)disulfide, dibutyl tetrasulfide, sulfurized methyl
ester of oleic acid, sulfurized alkylphenol, sulfurized dipentene,
and sulfurized terpene; phosphosulfiirized hydrocarbons such as the
reaction product of a phosphorus sulfide with turpentine or methyl
oleate, phosphorus esters including principally dihydrocarbon and
trihydrocarbon phosphites such as dibutyl phosphite, diheptyl
phosphite, dicyclohexyl phosphite, pentylphenyl phosphite,
dipentylphenyl phosphite, tridecyl phosphite, distearyl phosphite,
dimethyl naphthyl phosphite, oleyl 4-pentylphenyl phosphite,
polypropylene (molecular weight 500)-substituted phenyl phosphite,
diisobutyl-substituted phenyl phosphite; metal thiocarbamates, such
as zinc dioctyldithiocarbamate, and barium heptylphenyl
dithiocarbamate; Group II metal phosphorodithioates such as zinc
dicyclohexylphosphorodithioate, zinc dioctylphosphorodithioate,
barium di(heptylphenyl)(phosphorodithioate, cadmium
dinonylphosphorodithioate, and the reaction of phosphorus
pentasulfide with an equimolar mixture of isopropyl alcohol,
4-methyl-2-pentanol, and n-hexyl alcohol.
[0083] Oxidation inhibitors including organic compounds containing
sulfur, nitrogen, phosphorus and some alkylphenols are useful
additives in the lubricating oil compositions of this disclosure.
Two general types of oxidation inhibitors are those that react with
the initiators, peroxy radicals, and hydroperoxides to form
inactive compounds, and those that decompose these materials to
form less active compounds. Examples are hindered (alkylated)
phenols, e.g.
6-di(tert-butyl)-4-methyl-phenol[2,6-di(tert-butyl)-p-cresol,
DBPC], and aromatic amines, e.g. N-phenyl-alpha-naphthalamine.
[0084] Sulfurized alkyl phenols and alkali or alkaline earth metal
salts thereof also are useful antioxidants.
[0085] Another class of antioxidant used in lubricating oil
compositions and which may also be present are oil-soluble copper
compounds. Any oil-soluble suitable copper compound may be blended
into the lubricating oil. Examples of suitable copper antioxidants
include copper dihydrocarbyl thio- or dithio-phosphates and copper
salts of carboxylic acid (naturally occurring or synthetic). Other
suitable copper salts include copper dithiacarbamates, sulphonates,
phenates, and acetylacetonates. Basic, neutral, or acidic copper
Cu(I) and or Cu(II) salts derived from alkenyl succinic acids or
anhydrides are known to be particularly useful.
[0086] A sulfur-containing antioxidant may be any and every
antioxidant containing sulfur, for example, including dialkyl
thiodipropionates such as dilauryl thiodipropionate and distearyl
thiodipropionate, dialkyldithiocarbamic acid derivatives (excluding
metal salts), bis(3,5-di-t-butyl-4-hydroxybenzyl)sulfide,
mercaptobenzothiazole, reaction products of phosphorus pentoxide
and olefins, and dicetyl sulfide. Of these, preferred are dialkyl
thiodipropionates such as dilauryl thiodipropionate and distearyl
thiodipropionate. The amine-type antioxidant includes, for example,
monoalkyldiphenylamines such as monooctyldiphenylamine and
monononyldiphenyl amine; dialkyldiphenylamines such as
4,4'-dibutyldiphenylamine, 4,4'-dipentyldiphenylamine,
4,4'-dihexyldiphenylamine, 4,4'-diheptyldiphenylamine,
4,4'-dioctyldiphenylamine and 4,4'-dinonyldiphenylamine;
polyalkyldiphenylamines such as tetrabutyldiphenylamine,
tetrahexyldiphenylamine, tetraoctyldiphenylamine and
tetranonyldiphenylamine; and naphthylamines such as
alpha-naphthylamine, phenyl-alpha-naphthylamine,
butylphenyl-alpha-naphthylamine, pentylphenyl-alpha-naphthylamine,
hexylphenyl-alpha-naphthylamine, heptylphenyl-alpha-naphthylamine,
octylphenyl-alpha-naphthyl amine and
nonylphenyl-alpha-naphthylamine. Of these, preferred are
dialkyldiphenylamines.
[0087] Examples of sulfur-based antioxidants include
dialkylsulphides such as didodecylsulphide and dioctadecylsulphide;
thiodipropionic acid esters such as didodecyl thiodipropionate,
dioctadecyl thiodipropionate, dimyristyl thiodipropionate and
dodecyloctadecyl thiodipropionate, and 2-mercaptobenzimidazole.
[0088] Such antioxidants may be used individually or as mixtures of
one or more types of antioxidants, the total amount employed being
an amount of about 0.01 to about 5 wt %, preferably 0.1 to about
4.5 wt %, more preferably 0.25 to 3 wt % (on an as-received
basis).
Detergents
[0089] The lubricating oil compositions include at least one
detergent. Illustrative detergents useful in this disclosure
include, for example, alkali metal detergents, alkaline earth metal
detergents, or mixtures of one or more alkali metal detergents and
one or more alkaline earth metal detergents. A typical detergent is
an anionic material that contains a long chain hydrophobic portion
of the molecule and a smaller anionic or oleophobic hydrophilic
portion of the molecule. The anionic portion of the detergent is
typically derived from an organic acid such as a sulfur acid,
carboxylic acid (e.g., salicylic acid), phosphorous acid, phenol,
or mixtures thereof. The counterion is typically an alkaline earth
or alkali metal.
[0090] The detergent is preferably a metal salt of an organic or
inorganic acid, a metal salt of a phenol, or mixtures thereof. The
metal is preferably selected from an alkali metal, an alkaline
earth metal, and mixtures thereof. The organic or inorganic acid is
selected from an aliphatic organic or inorganic acid, a
cycloaliphatic organic or inorganic acid, an aromatic organic or
inorganic acid, and mixtures thereof.
[0091] The metal is preferably selected from an alkali metal, an
alkaline earth metal, and mixtures thereof. More preferably, the
metal is selected from calcium (Ca), magnesium (Mg), and mixtures
thereof.
[0092] The organic acid or inorganic acid is preferably selected
from a sulfur acid, a carboxylic acid, a phosphorus acid, and
mixtures thereof.
[0093] Preferably, the metal salt of an organic or inorganic acid
or the metal salt of a phenol comprises calcium phenate, calcium
sulfonate, calcium salicylate, magnesium phenate, magnesium
sulfonate, magnesium salicylate, and mixtures thereof.
[0094] Salts that contain a substantially stochiometric amount of
the metal are described as neutral salts and have a total base
number (TBN, as measured by ASTM D2896) of from 0 to 80. Many
compositions are overbased, containing large amounts of a metal
base that is achieved by reacting an excess of a metal compound (a
metal hydroxide or oxide, for example) with an acidic gas (such as
carbon dioxide). Useful detergents can be neutral, mildly
overbased, or highly overbased. These detergents can be used in
mixtures of neutral, overbased, highly overbased calcium
salicylate, sulfonates, phenates and/or magnesium salicylate,
sulfonates, phenates. The TBN ranges can vary from low, medium to
high TBN products, including as low as 0 to as high as 600.
Preferably the TBN delivered by the detergent is between 1 and 20.
More preferably between 1 and 12. Mixtures of low, medium, high TBN
can be used, along with mixtures of calcium and magnesium metal
based detergents, and including sulfonates, phenates, salicylates,
and carboxylates. A detergent mixture with a metal ratio of 1, in
conjunction of a detergent with a metal ratio of 2, and as high as
a detergent with a metal ratio of 5, can be used. Borated
detergents can also be used.
[0095] Alkaline earth phenates are another useful class of
detergent. These detergents can be made by reacting alkaline earth
metal hydroxide or oxide (CaO, Ca(OH).sub.2, BaO, Ba(OH).sub.2,
MgO, Mg(OH).sub.2, for example) with an alkyl phenol or sulfurized
alkylphenol. Useful alkyl groups include straight chain or branched
C.sub.1-C.sub.30 alkyl groups, preferably, C.sub.4-C.sub.20 or
mixtures thereof. Examples of suitable phenols include
isobutylphenol, 2-ethylhexylphenol, nonylphenol, dodecyl phenol,
and the like. It should be noted that starting alkylphenols may
contain more than one alkyl substituent that are each independently
straight chain or branched and can be used from 0.5 to 6 weight
percent. When a non-sulfurized alkylphenol is used, the sulfurized
product may be obtained by methods well known in the art. These
methods include heating a mixture of alkylphenol and sulfurizing
agent (including elemental sulfur, sulfur halides such as sulfur
dichloride, and the like) and then reacting the sulfurized phenol
with an alkaline earth metal base.
[0096] Metal salts of carboxylic acids are useful detergents. These
carboxylic acid detergents may be prepared by reacting a basic
metal compound with at least one carboxylic acid and removing free
water from the reaction product. Detergents made from salicylic
acid are one preferred class of detergents derived from carboxylic
acids. Useful salicylates include long chain alkyl salicylates. One
useful family of compositions is of the formula
##STR00004##
where R is an alkyl group having 1 to about 30 carbon atoms, n is
an integer from 1 to 4, and M is an alkaline earth metal. Preferred
R groups are alkyl chains of at least C.sub.11, preferably C.sub.13
or greater. R may be optionally substituted with substituents that
do not interfere with the detergent's function. M is preferably,
calcium, magnesium, or barium. More preferably, M is calcium.
[0097] Hydrocarbyl-substituted salicylic acids may be prepared from
phenols by the Kolbe reaction (see U.S. Pat. No. 3,595,791). The
metal salts of the hydrocarbyl-substituted salicylic acids may be
prepared by double decomposition of a metal salt in a polar solvent
such as water or alcohol.
[0098] Alkaline earth metal phosphates are also used as detergents
and are known in the art.
[0099] Detergents may be simple detergents or what is known as
hybrid or complex detergents. The latter detergents can provide the
properties of two detergents without the need to blend separate
materials. See U.S. Pat. No. 6,034,039.
[0100] Illustrative detergents include calcium alkylsalicylates,
calcium alkylphenates and calcium alkarylsulfonates with alternate
metal ions used such as magnesium, barium, or sodium. Examples of
the cleaning and dispersing agents which can be used include
metal-based detergents such as the neutral and basic alkaline earth
metal sulphonates, alkaline earth metal phenates and alkaline earth
metal salicylates alkenylsuccinimide and alkenylsuccinimide esters
and their borohydrides, phenates, salienius complex detergents and
ashless dispersing agents which have been modified with sulfur
compounds. These agents can be added and used individually or in
the form of mixtures, conveniently in an amount within the range of
from 0.01 to 1 part by weight per 100 parts by weight of base oil;
these can also be high TBN, low TBN, or mixtures of high/low
TBN.
[0101] Preferred detergents include calcium sulfonates, magnesium
sulfonates, calcium salicylates, magnesium salicylates, calcium
phenates, magnesium phenates, and other related components
(including borated detergents), and mixtures thereof. Preferred
mixtures of detergents include magnesium sulfonate and calcium
salicylate, magnesium sulfonate and calcium sulfonate, magnesium
sulfonate and calcium phenate, calcium phenate and calcium
salicylate, calcium phenate and calcium sulfonate, calcium phenate
and magnesium salicylate, calcium phenate and magnesium
phenate.
[0102] The detergent concentration in the lubricating oils of this
disclosure can range from about 0.01 to about 10 weight percent,
preferably about 0.1 to 7.5 weight percent, and more preferably
from about 0.5 weight percent to about 5 weight percent, based on
the total weight of the lubricating oil.
[0103] As used herein, the detergent concentrations are given on an
"as delivered" basis. Typically, the active detergent is delivered
with a process oil. The "as delivered" detergent typically contains
from about 20 weight percent to about 100 weight percent, or from
about 40 weight percent to about 60 weight percent, of active
detergent in the "as delivered" detergent product.
Dispersants
[0104] The lubricating oil compositions include at least one
dispersant. During engine operation, oil-insoluble oxidation
byproducts are produced. Dispersants help keep these byproducts in
solution, thus diminishing their deposition on metal surfaces.
Dispersants used in the formulating of the lubricating oil may be
ashless or ash-forming in nature. Preferably, the dispersant is
ashless. So called ashless dispersants are organic materials that
form substantially no ash upon combustion. For example,
non-metal-containing or borated metal-free dispersants are
considered ashless.
[0105] Suitable dispersants typically contain a polar group
attached to a relatively high molecular weight hydrocarbon chain.
The polar group typically contains at least one element of
nitrogen, oxygen, or phosphorus. Typical hydrocarbon chains contain
50 to 400 carbon atoms.
[0106] A particularly useful class of dispersants are the
(poly)alkenylsuccinic derivatives, typically produced by the
reaction of a long chain hydrocarbyl substituted succinic compound,
usually a hydrocarbyl substituted succinic anhydride, with a
polyhydroxy or polyamino compound. The long chain hydrocarbyl group
constituting the oleophilic portion of the molecule which confers
solubility in the oil, is normally a polyisobutylene group. Many
examples of this type of dispersant are well known commercially and
in the literature. Exemplary U.S. patents describing such
dispersants are U.S. Pat. Nos. 3,172,892; 3,2145,707; 3,219,666;
3,316,177; 3,341,542; 3,444,170; 3,454,607; 3,541,012; 3,630,904;
3,632,511; 3,787,374 and 4,234,435. Other types of dispersant are
described in U.S. Pat. Nos. 3,036,003; 3,200,107; 3,254,025;
3,275,554; 3,438,757; 3,454,555; 3,565,804; 3,413,347; 3,697,574;
3,725,277; 3,725,480; 3,726,882; 4,454,059; 3,329,658; 3,449,250;
3,519,565; 3,666,730; 3,687,849; 3,702,300; 4,100,082; 5,705,458. A
further description of dispersants may be found, for example, in
European Patent Application No. 471 071, to which reference is made
for this purpose.
[0107] Hydrocarbyl-substituted succinic acid and
hydrocarbyl-substituted succinic anhydride derivatives are useful
dispersants. In particular, succinimide, succinate esters, or
succinate ester amides prepared by the reaction of a
hydrocarbon-substituted succinic acid compound preferably having at
least 50 carbon atoms in the hydrocarbon substituent, with at least
one equivalent of an alkylene amine are particularly useful.
[0108] Succinimides are formed by the condensation reaction between
hydrocarbyl substituted succinic anhydrides and amines. Molar
ratios can vary depending on the polyamine. For example, to the
molar ratio of hydrocarbyl substituted succinic anhydride to TEPA
can vary from about 1:1 to about 5:1. Representative examples are
shown in U.S. Pat. Nos. 3,087,936; 3,172,892; 3,219,666; 3,272,746;
3,322,670; and U.S. Pat. Nos. 3,652,616, 3,948,800.
[0109] Succinate esters are formed by the condensation reaction
between hydrocarbyl substituted succinic anhydrides and alcohols or
polyols. Molar ratios can vary depending on the alcohol or polyol
used. For example, the condensation product of a hydrocarbyl
substituted succinic anhydride and pentaerythritol is a useful
dispersant.
[0110] Succinate ester amides are formed by condensation reaction
between hydrocarbyl substituted succinic anhydrides and alkanol
amines. For example, suitable alkanol amines include ethoxylated
polyalkylpolyamines, propoxylated polyalkylpolyamines and
polyalkenylpolyamines such as polyethylene polyamines. One example
is propoxylated hexamethylenediamine. Representative examples are
shown in U.S. Pat. No. 4,426,305.
[0111] The molecular weight of the hydrocarbyl substituted succinic
anhydrides used in the preceding paragraphs will typically range
between 800 and 2,500 or more. The above products can be
post-reacted with various reagents such as sulfur, oxygen,
formaldehyde, carboxylic acids such as oleic acid. The above
products can also be post reacted with boron compounds such as
boric acid, borate esters or highly borated dispersants, to form
borated dispersants generally having from about 0.1 to about 5
moles of boron per mole of dispersant reaction product. Further,
metal modified versions of the above succinic derived dispersants
are known, with illustrative examples that include zinc-modified
alkyl succinimide types.
[0112] Mannich base dispersants are made from the reaction of
alkylphenols, formaldehyde, and amines. See U.S. Pat. No.
4,767,551, which is incorporated herein by reference. Process aids
and catalysts, such as oleic acid and sulfonic acids, can also be
part of the reaction mixture. Molecular weights of the alkylphenols
range from 800 to 2,500. Representative examples are shown in U.S.
Pat. Nos. 3,697,574; 3,703,536; 3,704,308; 3,751,365; 3,756,953;
3,798,165; and 3,803,039.
[0113] Typical high molecular weight aliphatic acid modified
Mannich condensation products useful in this disclosure can be
prepared from high molecular weight alkyl-substituted
hydroxyaromatics or HNR.sub.2 group-containing reactants.
[0114] Hydrocarbyl substituted amine ashless dispersant additives
are well known to one skilled in the art; see, for example, U.S.
Pat. Nos. 3,275,554; 3,438,757; 3,565,804; 3,755,433, 3,822,209,
and 5,084,197.
[0115] Illustrative dispersants include borated and non-borated
succinimides, including those derivatives from mono-succinimides,
bis-succinimides, and/or mixtures of mono- and bis-succinimides,
wherein the hydrocarbyl succinimide is derived from a
hydrocarbylene group such as polyisobutylene having a Mn of from
about 500 to about 5000, or from about 1000 to about 3000, or about
1000 to about 2000, or a mixture of such hydrocarbylene groups,
often with high terminal vinylic groups. Other preferred
dispersants include succinic acid-esters and amides,
alkylphenol-polyamine-coupled Mannich adducts, their capped
derivatives, and other related components.
[0116] Polymethacrylate or polyacrylate derivatives are another
class of dispersants. These dispersants are typically prepared by
reacting a nitrogen containing monomer and a methacrylic or acrylic
acid esters containing 5-25 carbon atoms in the ester group.
Representative examples are shown in U.S. Pat. Nos. 2,100,993, and
6,323,164. Polymethacrylate and polyacrylate dispersants are
normally used as multifunctional viscosity modifiers. The lower
molecular weight versions can be used as lubricant dispersants or
fuel detergents.
[0117] Other illustrative dispersants useful in this disclosure
include those derived from polyalkenyl-substituted mono- or
dicarboxylic acid, anhydride or ester, which dispersant has a
polyalkenyl moiety with a number average molecular weight of at
least 900 and from greater than 1.3 to 1.7, preferably from greater
than 1.3 to 1.6, most preferably from greater than 1.3 to 1.5,
functional groups (mono- or dicarboxylic acid producing moieties)
per polyalkenyl moiety (a medium functionality dispersant).
Functionality (F) can be determined according to the following
formula:
F=(SAP.times.M.sub.n)/((112,200.times.A.I.)-(SAP.times.98))
wherein SAP is the saponification number (i.e., the number of
milligrams of KOH consumed in the complete neutralization of the
acid groups in one gram of the succinic-containing reaction
product, as determined according to ASTM D94); M.sub.n is the
number average molecular weight of the starting olefin polymer; and
A.I. is the percent active ingredient of the succinic-containing
reaction product (the remainder being unreacted olefin polymer,
succinic anhydride and diluent).
[0118] The polyalkenyl moiety of the dispersant may have a number
average molecular weight of at least 900, suitably at least 1500,
preferably between 1800 and 3000, such as between 2000 and 2800,
more preferably from about 2100 to 2500, and most preferably from
about 2200 to about 2400. The molecular weight of a dispersant is
generally expressed in terms of the molecular weight of the
polyalkenyl moiety. This is because the precise molecular weight
range of the dispersant depends on numerous parameters including
the type of polymer used to derive the dispersant, the number of
functional groups, and the type of nucleophilic group employed.
[0119] Polymer molecular weight, specifically M.sub.n, can be
determined by various known techniques. One convenient method is
gel permeation chromatography (GPC), which additionally provides
molecular weight distribution information (see W. W. Yau, J. J.
Kirkland and D. D. Bly, "Modern Size Exclusion Liquid
Chromatography", John Wiley and Sons, New York, 1979). Another
useful method for determining molecular weight, particularly for
lower molecular weight polymers, is vapor pressure osmometry (e.g.,
ASTM D3592).
[0120] The polyalkenyl moiety in a dispersant preferably has a
narrow molecular weight distribution (MWD), also referred to as
polydispersity, as determined by the ratio of weight average
molecular weight (M.sub.w) to number average molecular weight
(M.sub.n). Polymers having a M.sub.w/M.sub.n of less than 2.2,
preferably less than 2.0, are most desirable. Suitable polymers
have a polydispersity of from about 1.5 to 2.1, preferably from
about 1.6 to about 1.8.
[0121] Suitable polyalkenes employed in the formation of the
dispersants include homopolymers, interpolymers or lower molecular
weight hydrocarbons. One family of such polymers comprise polymers
of ethylene and/or at least one C.sub.3 to C.sub.24 alpha-olefin.
Preferably, such polymers comprise interpolymers of ethylene and at
least one alpha-olefin of the above formula.
[0122] Another useful class of polymers is polymers prepared by
cationic polymerization of monomers such as isobutene and styrene.
Common polymers from this class include polyisobutenes obtained by
polymerization of a C.sub.4 refinery stream having a butene content
of 35 to 75% by wt., and an isobutene content of 30 to 60% by wt. A
preferred source of monomer for making poly-n-butenes is petroleum
feedstreams such as Raffinate II. These feedstocks are disclosed in
the art such as in U.S. Pat. No. 4,952,739. A preferred embodiment
utilizes polyisobutylene prepared from a pure isobutylene stream or
a Raffinate I stream to prepare reactive isobutylene polymers with
terminal vinylidene olefins. Polyisobutene polymers that may be
employed are generally based on a polymer chain of from 1500 to
3000.
[0123] Dispersants that contain the alkenyl or alkyl group have an
M.sub.n value of about 500 to about 5000 and an M.sub.w/M.sub.n
ratio of about 1 to about 5. The preferred M.sub.n intervals depend
on the chemical nature of the agent improving filterability.
Polyolefinic polymers suitable for the reaction with maleic
anhydride or other acid materials or acid forming materials,
include polymers containing a predominant quantity of C.sub.2 to
C.sub.5 monoolefins, for example, ethylene, propylene, butylene,
isobutylene and pentene. A highly suitable polyolefinic polymer is
polyisobutene. The succinic anhydride preferred as a reaction
substance is PIBSA, that is, polyisobutenyl succinic anhydride.
[0124] If the dispersant contains a succinimide comprising the
reaction product of a succinic to anhydride with a polyamine, the
alkenyl or alkyl substituent of the succinic anhydride serving as
the reaction substance consists preferably of polymerised isobutene
having an Mn value of about 1200 to about 2500. More
advantageously, the alkenyl or alkyl substituent of the succinic
anhydride serving as the reaction substance consists in a
polymerised isobutene having an Mn value of about 2100 to about
2400. If the agent improving filterability contains an ester of
succinic acid comprising the reaction product of a succinic
anhydride and an aliphatic polyhydric alcohol, the alkenyl or alkyl
substituent of the succinic anhydride serving as the reaction
substance consists advantageously of a polymerised isobutene having
an Mn value of 500 to 1500. In preference, a polymerised isobutene
having an Mn value of 850 to 1200 is used.
[0125] The amides may be amides of mono- or polycarboxylic acids or
reactive derivatives thereof. The amides may be characterized by a
hydrocarbyl group containing from about 6 to about 90 carbon atoms;
each is independently hydrogen or a hydrocarbyl, aminohydrocarbyl,
hydroxyhydrocarbyl or a heterocyclic-substituted hydrocarbyl group,
provided that both are not hydrogen; each is, independently, a
hydrocarbylene group containing up to about 10 carbon atoms.
[0126] The amide can be derived from a monocarboxylic acid, a
hydrocarbyl group containing from 6 to about 30 or 38 carbon atoms
and more often will be a hydrocarbyl group derived from a fatty
acid containing from 12 to about 24 carbon atoms.
[0127] An illustrative amide that is derived from a di- or
tricarboxylic acid, will contain from 6 to about 90 or more carbon
atoms depending on the type of polycarboxylic acid. For example,
when the amide is derived from a dimer acid, will contain from
about 18 to about 44 carbon atoms or more, and amides derived from
trimer acids generally will contain an average of from about 44 to
about 90 carbon atoms. Each is independently hydrogen or a
hydrocarbyl, aminohydrocarbyl, hydroxyhydrocarbyl or a
heterocyclic-substituted hydrocarbon group containing up to about
10 carbon atoms. It may be independently heterocyclic substituted
hydrocarbyl groups wherein the heterocyclic substituent is derived
from pyrrole, pyrroline, pyrrolidine, morpholine, piperazine,
piperidine, pyridine, pipecoline, etc. Specific examples include
methyl, ethyl, n-propyl, n-butyl, n-hexyl, hydroxymethyl,
hydroxyethyl, hydroxypropyl, amino-methyl, aminoethyl, aminopropyl,
2-ethylpyridine, 1-ethylpyrrolidine, 1-ethylpiperidine, etc.
[0128] Illustrative aliphatic monoamines include mono-aliphatic and
di-aliphatic-substituted amines wherein the aliphatic groups may be
saturated or unsaturated and straight chain or branched chain. Such
amines include, for example, mono- and di-alkyl-substituted amines,
mono- and dialkenyl-substituted amines, etc. Specific examples of
such monoamines include ethyl amine, diethyl amine, n-butyl amine,
di-n-butyl amine, isobutyl amine, coco amine, stearyl amine, oleyl
amine, etc. An example of a cycloaliphatic-substituted aliphatic
amine is 2-(cyclohexyl)-ethyl amine. Examples of
heterocyclic-substituted aliphatic amines include
2-(2-aminoethyl)-pyrrole, 2-(2-aminoethyl)-1-methylpyrrole,
2-(2-aminoethyl)-1-methylpyrrolidine and
4-(2-aminoethyl)morpholine, 1-(2-aminoethyl)piperazine,
1-(2-aminoethyl)piperidine, 2-(2-aminoethyl)pyridine,
1-(2-aminoethyl)pyrrolidine, 1-(3-aminopropyl)imidazole,
3-(2-aminopropyl)indole, 4-(3-aminopropyl)morpholine,
1-(3-aminopropyl)-2-pipecoline, 1-(3-aminopropyl)-2-pyrrolidinone,
etc.
[0129] Illustrative cycloaliphatic monoamines are those monoamines
wherein there is one cycloaliphatic substituent attached directly
to the amino nitrogen through a carbon atom in the cyclic ring
structure. Examples of cycloaliphatic monoamines include
cyclohexylamines, cyclopentylamines, cyclohexenylamines,
cyclopentenylamines, N-ethyl-cyclohexylamine, dicyclohexylamines,
and the like. Examples of aliphatic-substituted,
aromatic-substituted, and heterocyclic-substituted cycloaliphatic
monoamines include propyl-substituted cyclohexylamines,
phenyl-substituted cyclopentylamines, and pyranyl-substituted
cyclohexylamine.
[0130] Illustrative aromatic amines include those monoamines
wherein a carbon atom of the aromatic ring structure is attached
directly to the amino nitrogen. The aromatic ring will usually be a
mononuclear aromatic ring (i.e., one derived from benzene) but can
include fused aromatic rings, especially those derived from
naphthalene. Examples of aromatic monoamines include aniline,
di-(para-methylphenyl)amine, naphthylamine, N-(n-butyl)-aniline,
and the like. Examples of aliphatic-substituted,
cycloaliphatic-substituted, and heterocyclic-substituted aromatic
monoamines are para-ethoxy-aniline, para-dodecylaniline,
cyclohexyl-substituted naphthylamine, variously substituted
phenathiazines, and thienyl-substituted aniline.
[0131] Illustrative polyamines are aliphatic, cycloaliphatic and
aromatic polyamines analogous to the above-described monoamines
except for the presence within their structure of additional amino
nitrogens. The additional amino nitrogens can be primary, secondary
or tertiary amino nitrogens. Examples of such polyamines include
N-amino-propyl-cyclohexylamines, N,N'-di-n-butyl-paraphenylene
diamine, bis-(para-aminophenyl)methane, 1,4-diaminocyclohexane, and
the like.
[0132] Illustrative hydroxy-substituted amines are those having
hydroxy substituents bonded directly to a carbon atom other than a
carbonyl carbon atom; that is, they have hydroxy groups capable of
functioning as alcohols. Examples of such hydroxy-substituted
amines include ethanolamine, di-(3-hydroxypropyl)-amine, 3-hydroxy
butyl-amine, 4-hydroxy butyl-amine, diethanolamine,
di-(2-hydroxyamine, N-(hydroxypropyl)-propylamine,
N-(2-methyl)-cyclohexylamine, 3-hydroxycyclopentyl
parahydroxyaniline, N-hydroxyethal piperazine and the like.
[0133] In one embodiment, the amines are alkylene polyamines
including hydrogen, or a hydrocarbyl, amino hydrocarbyl,
hydroxyhydrocarbyl or heterocyclic-substituted hydrocarbyl group
containing up to about 10 carbon atoms. Examples of such alkylene
polyamines include methylene polyamines, ethylene polyamines,
butylene polyamines, propylene polyamines, pentylene polyamines,
hexylene polyamines, heptylene polyamines, etc.
[0134] Alkylene polyamines include ethylene diamine, triethylene
tetramine, propylene diamine, trimethylene diamine, hexamethylene
diamine, decamethylene diamine, hexamethylene diamine,
decamethylene diamine, octamethylene diamine, di(heptamethylene)
triamine, tripropylene tetramine, tetraethylene pentamine,
trimethylene diamine, pentaethylene hexamine,
di(trimethylene)triamine, and the like. Higher homologs as are
obtained by condensing two or more of the above-illustrated
alkylene amines are useful, as are mixtures of two or more of any
of the afore-described polyamines.
[0135] Ethylene polyamines, such as those mentioned above, are
especially useful for reasons of cost and effectiveness. Such
polyamines are described in detail under the heading "Diamines and
Higher Amines" in The Encyclopedia of Chemical Technology, Second
Edition, Kirk and Othmer, Volume 7, pages 27-39, Interscience
Publishers, Division of John Wiley and Sons, 1965, which is hereby
incorporated by reference for the disclosure of useful polyamines.
Such compounds are prepared most conveniently by the reaction of an
alkylene chloride with ammonia or by reaction of an ethylene imine
with a ring-opening reagent such as ammonia, etc. These reactions
result in the production of the somewhat complex mixtures of
alkylene polyamines, including cyclic condensation products such as
piperazines.
[0136] Other useful types of polyamine mixtures are those resulting
from stripping of the above-described polyamine mixtures. In this
instance, lower molecular weight polyamines and volatile
contaminants are removed from an alkylene polyamine mixture to
leave as residue what is often termed "polyamine bottoms". In
general, alkylene polyamine bottoms can be characterized as having
less than 2, usually less than 1% (by weight) material boiling
below about 200.degree. C. In the instance of ethylene polyamine
bottoms, which are readily available and found to be quite useful,
the bottoms contain less than about 2% (by weight) total diethylene
triamine (DETA) or triethylene tetramine (TETA). A typical sample
of such ethylene polyamine bottoms obtained from the Dow Chemical
Company of Freeport, Tex. designated "E-100". Gas chromatography
analysis of such a sample showed it to contain about 0.93% "Light
Ends" (most probably DETA), 0.72% TETA, 21.74% tetraethylene
pentamine and 76.61% pentaethylene hexamine and higher (by weight).
These alkylene polyamine bottoms include cyclic condensation
products such as piperazine and higher analogs of diethylene
triamine, triethylene tetramine and the like.
[0137] Illustrative dispersants are selected from: Mannich bases
that are condensation reaction products of a high molecular weight
phenol, an alkylene polyamine and an aldehyde such as formaldehyde;
succinic-based dispersants that are reaction products of a olefin
polymer and succinic acylating agent (acid, anhydride, ester or
halide) further reacted with an organic hydroxy compound and/or an
amine; high molecular weight amides and esters such as reaction
products of a hydrocarbyl acylating agent and a polyhydric
aliphatic alcohol (such as glycerol, pentaerythritol or sorbitol).
Ashless (metal-free) polymeric materials that usually contain an
oil soluble high molecular weight backbone linked to a polar
functional group that associates with particles to be dispersed are
typically used as dispersants. Zinc acetate capped, also any
treated dispersant, which include borated, cyclic carbonate,
end-capped, polyalkylene maleic anhydride and the like; mixtures of
some of the above, in treat rates that range from about 0.1% up to
10-20% or more. Commonly used hydrocarbon backbone materials are
olefin polymers and copolymers, i.e., ethylene, propylene,
butylene, isobutylene, styrene; there may or may not be further
functional groups incorporated into the backbone of the polymer,
whose molecular weight ranges from 300 to 5000. Polar materials
such as amines, alcohols, amides or esters are attached to the
backbone via a bridge.
[0138] The dispersant(s) are preferably non-polymeric (e.g., mono-
or bis-succinimides). Such dispersants can be prepared by
conventional processes such as disclosed in U.S. Patent Application
Publication No. 2008/0020950, the disclosure of which is
incorporated herein by reference.
[0139] The dispersant(s) can be borated by conventional means, as
generally disclosed in U.S. Pat. Nos. 3,087,936, 3,254,025 and
5,430,105.
[0140] Such dispersants may be used in an amount of about 0.01 to
20 weight percent or 0.01 to 10 weight percent, preferably about
0.5 to 8 weight percent, or more preferably 0.5 to 4 weight
percent. Or such dispersants may be used in an amount of about 2 to
12 weight percent, preferably about 4 to 10 weight percent, or more
preferably 6 to 9 weight percent. On an active ingredient basis,
such additives may be used in an amount of about 0.06 to 14 weight
percent, preferably about 0.3 to 6 weight percent. The hydrocarbon
portion of the dispersant atoms can range from C.sub.60 to
C.sub.1000, or from C.sub.70 to C.sub.300, or from C.sub.70 to
C.sub.200. These dispersants may contain both neutral and basic
nitrogen, and mixtures of both. Dispersants can be end-capped by
borates and/or cyclic carbonates. Nitrogen content in the finished
oil can vary from about 200 ppm by weight to about 2000 ppm by
weight, preferably from about 200 ppm by weight to about 1200 ppm
by weight. Basic nitrogen can vary from about 100 ppm by weight to
about 1000 ppm by weight, preferably from about 100 ppm by weight
to about 600 ppm by weight.
[0141] As used herein, the dispersant concentrations are given on
an "as delivered" basis. Typically, the active dispersant is
delivered with a process oil. The "as delivered" dispersant
typically contains from about 20 weight percent to about 80 weight
percent, or from about 40 weight percent to about 60 weight
percent, of active dispersant in the "as delivered" dispersant
product.
Antiwear Additives
[0142] The lubricating oil compositions include at least one
antiwear agent. Examples of suitable antiwear agents include oil
soluble amine salts of phosphorus compounds, sulfurized olefins,
metal dihydrocarbyldithio-phosphates (such as zinc
dialkyldithiophosphates), thiocarbamate-containing compounds, such
as thiocarbamate esters, thiocarbamate amides, thiocarbamic ethers,
alkylene-coupled thiocarbamates, and bis(S-alkyldithiocarbamyl)
disulphides.
[0143] Antiwear agents used in the formulating of the lubricating
oil may be ashless or ash-forming in nature. Preferably, the
antiwear agent is ashless. So called ashless antiwear agents are
materials that form substantially no ash upon combustion. For
example, non-metal-containing antiwear agents are considered
ashless.
[0144] In one embodiment, oil soluble phosphorus amine antiwear
agents include an amine salt of a phosphorus acid ester or mixtures
thereof. The amine salt of a phosphorus acid ester includes
phosphoric acid esters and amine sails thereof;
dialkyldithiophosphoric acid esters and amine salts thereof, amine
salts of phosphites; and amine salts of phosphorus-containing
carboxylic esters, ethers, and amides; and mixtures thereof. The
amine salt of a phosphorus acid ester may be used alone or in
combination.
[0145] In one embodiment, oil soluble phosphorus amine salts
include partial amine salt-partial metal salt compounds or mixtures
thereof. In one embodiment, the phosphorus compound further
includes a sulfur atom in the molecule. In one embodiment, the
amine salt of the phosphorus compound may be ashless, i.e.,
metal-free (prior to being mixed with other components).
[0146] The amines which may be suitable for use as the amine salt
include primary amines, secondary amines, tertiary amines, and
mixtures thereof. The amines include those with at least one
hydrocarbyl group, or, in certain embodiments, two or three
hydrocarbyl groups. The hydrocarbyl groups may contain 2 to 30
carbon atoms, or in other embodiments 8 to 26, or 10 to 20, or 13
to 19 carbon atoms.
[0147] Primary amines include ethylamine, propylamine, butylamine,
2-ethylhexylamine, octylamine, and dodecylamine, as well as such
fatty amines as n-octylamine, n-decylamine, n-dodeclyamine,
n-tetradecylamine, n-hexadecylamine, n-octadecylamine and
oleyamine. Other useful fatty amines include commercially available
fatty amines such as "Armeen.TM." amines (products available from
Akzo Chemicals, Chicago, Ill.), such as Armeen C, Armeen O, Armeen
OL, Armeen T, Armeen HT, Armeen S and Armeen S D, wherein the
letter designation relates to the fatty group, such as coco, oleyl,
tallow, or stearyl groups.
[0148] Examples of suitable secondary amines include dim
ethylamine, diethylamine, dipropylamine, dibutylamine, diamylamine,
dihexylamine, diheptylamine, methylethylamine, ethylbutylamine and
ethylamylamine. The secondary amines may be cyclic amines such as
piperidine, piperazine and morpholine.
[0149] The amine may also be a tertiary-aliphatic primary amine.
The aliphatic group in this case may be an alkyl group containing 2
to 30, or 6 to 26, or 8 to 24 carbon atoms. Tertiary alkyl amines
include monoamines such as tert-butylamine, tert-hexylamine,
1-methyl-1-amino-cyclohexane, tert-octylamine, tert-decylamine,
tertdodecylamine, tert-tetradecylamine, tert-hexadecylamine,
tert-octadecylamine, tert-tetracosanylamine, and
tert-octacosanylamine.
[0150] In one embodiment, the phosphorus acid amine salt includes
an amine with C.sub.11 to C.sub.14 tertiary alkyl primary groups or
mixtures thereof. In one embodiment the phosphorus acid amine salt
includes an amine with C.sub.14 to C.sub.18 tertiary alkyl primary
amines or mixtures thereof. In one embodiment the phosphorus acid
amine salt includes an amine with C.sub.18 to C.sub.22 tertiary
alkyl primary amines or mixtures thereof.
[0151] Mixtures of amines may also be used in the disclosure. In
one embodiment a useful mixture of amines is "Primene.TM. 81R" and
"Primene.TM. JMT." Primene.TM. 81R and Primene.TM. JMT (both
produced and sold by Rohm & Haas) are mixtures of C.sub.11 to
C.sub.14 tertiary alkyl primary amines and C.sub.18 to C.sub.22
tertiary alkyl primary amines respectively.
[0152] In one embodiment, oil soluble amine salts of phosphorus
compounds include a sulfur-free amine salt of a
phosphorus-containing compound may be obtained/obtainable by a
process comprising: reacting an amine with either (i) a
hydroxy-substituted di-ester of phosphoric acid, or (ii) a
phosphorylated hydroxy-substituted di- or tri-ester of phosphoric
acid. A more detailed description of compounds of this type is
disclosed in International Application PCT/US08/051126.
[0153] In one embodiment, the hydrocarbyl amine salt of an
alkylphosphoric acid ester is the reaction product of a C.sub.14 to
C.sub.18 alkylated phosphoric acid with Primene 81RT.TM. (produced
and sold by Rohm & Haas) which is a mixture of C.sub.11 to
C.sub.14 tertiary alkyl primary amines.
[0154] Examples of hydrocarbyl amine salts of
dialkyldithiophosphoric acid esters include the reaction product(s)
of isopropyl, methyl-amyl (4-methyl-2-pentyl or mixtures thereof),
2-ethylhexyl, heptyl, octyl or nonyl dithiophosphoric acids with
ethylene diamine, morpholine, or Primene 81R.TM., and mixtures
thereof.
[0155] In one embodiment, the dithiophosphoric acid may be reacted
with an epoxide or a glycol. This reaction product is further
reacted with a phosphorus acid, anhydride, or lower ester. The
epoxide includes an aliphatic epoxide or a styrene oxide. Examples
of useful epoxides include ethylene oxide, propylene oxide, butene
oxide, octene oxide, dodecene oxide, and styrene oxide. In one
embodiment, the epoxide may be propylene oxide. The glycols may be
aliphatic glycols having from 1 to 12, or from 2 to 6, or 2 to 3
carbon atoms. The dithiophosphoric acids, glycols, epoxides,
inorganic phosphorus reagents and methods of reacting the same are
described in U.S. Pat. Nos. 3,197,405 and 3,544,465. The resulting
acids may then be salted with amines.
[0156] The dithiocarbamate-containing compounds may be prepared by
reacting a dithiocarbamate acid or salt with an unsaturated
compound. The dithiocarbamate containing compounds may also be
prepared by simultaneously reacting an amine, carbon disulphide and
an unsaturated compound. Generally, the reaction occurs at a
temperature from 25.degree. C. to 125.degree. C.
[0157] Examples of suitable olefins that may be sulfurized to form
the sulfurized olefin include propylene, butylene, isobutylene,
pentene, hexane, heptene, octane, nonene, decene, undecene,
dodecene, undecyl, tridecene, tetradecene, pentadecene, hexadecene,
heptadecene, octadecene, octadecenene, nonodecene, eicosene or
mixtures thereof. In one embodiment, hexadecene, heptadecene,
octadecene, octadecenene, nonodecene, eicosene or mixtures thereof
and their dimers, trimers and tetramers are especially useful
olefins. Alternatively, the olefin may be a Diels-Alder adduct of a
diene such as 1,3-butadiene and an unsaturated ester, such as,
butylacrylate.
[0158] Another class of sulfurized olefin includes fatty acids and
their esters. The fatty acids are often obtained from vegetable oil
or animal oil; and typically contain 4 to 22 carbon atoms. Examples
of suitable fatty acids and their esters include triglycerides,
oleic acid, linoleic acid, palmitoleic acid or mixtures thereof.
Often, the fatty acids are obtained from lard oil, tall oil, peanut
oil, soybean oil, cottonseed oil, sunflower seed oil or mixtures
thereof. In one embodiment fatty acids and/or ester are mixed with
olefins.
[0159] Polyols include diols, triols, and alcohols with higher
numbers of alcoholic OH groups. Polyhydric alcohols include
ethylene glycols, including di-, tri- and tetraethylene glycols;
propylene glycols, including di-, tri- and tetrapropylene glycols;
glycerol; butane diol; hexane diol; sorbitol; arabitol; mannitol;
sucrose; fructose; glucose; cyclohexane diol; erythritol; and
penta-erythritols, including di- and tripentaerythritol. Often the
polyol is diethylene glycol, triethylene glycol, glycerol,
sorbitol, penta erythritol or dipentaerythritol.
[0160] In an alternative embodiment, the ashless antiwear agent may
be a monoester of a polyol and an aliphatic carboxylic acid, often
an acid containing 12 to 24 carbon atoms. Often the monoester of a
polyol and an aliphatic carboxylic acid is in the form of a mixture
with a sunflower to oil or the like, which may be present in the
mixture from 5 to 95, in several embodiments from 10 to 90, or from
20 to 85, or 20 to 80 weight percent of said mixture. The aliphatic
carboxylic acids (especially a monocarboxylic acid) which form the
esters are those acids typically containing 12 to 24, or from 14 to
20 carbon atoms. Examples of carboxylic acids include dodecanoic
acid, stearic acid, lauric acid, behenic acid, and oleic acid.
[0161] Illustrative antiwear additives useful in this disclosure
include, for example, metal salts of a carboxylic acid. The metal
is selected from a transition metal and mixtures thereof. The
carboxylic acid is selected from an aliphatic carboxylic acid, a
cycloaliphatic carboxylic acid, an aromatic carboxylic acid, and
mixtures thereof.
[0162] The metal is preferably selected from a Group 10, 11 and 12
metal, and mixtures thereof. The carboxylic acid is preferably an
aliphatic, saturated, unbranched carboxylic acid having from about
8 to about 26 carbon atoms, and mixtures thereof.
[0163] The metal is preferably selected from nickel (Ni), palladium
(Pd), platinum (Pt), copper (Cu), silver (Ag), gold (Au), zinc
(Zn), and mixtures thereof.
[0164] The carboxylic acid is preferably selected from caprylic
acid (C8), pelargonic acid (C9), capric acid (C10), undecylic acid
(C11), lauric acid (C12), tridecylic acid (C13), myristic acid
(C14), pentadecylic acid (C15), palmitic acid (C16), margaric acid
(C17), stearic acid (C18), nonadecylic acid (C19), arachidic acid
(C20), heneicosylic acid (C21), behenic acid (C22), tricosylic acid
(C23), lignoceric acid (C24), pentacosylic acid (C25), cerotic acid
(C26), and mixtures thereof.
[0165] Preferably, the metal salt of a carboxylic acid comprises
zinc stearate, silver stearate, palladium stearate, zinc palmitate,
silver palmitate, palladium palmitate, and mixtures thereof.
[0166] The metal salt of a carboxylic acid is present in the engine
oil compositions of this disclosure in an amount of from about 0.01
weight percent to about 5 weight percent, based on the total weight
of the lubricating oil composition.
[0167] A metal alkylthiophosphate and more particularly a metal
dialkyl dithio phosphate in which the metal constituent is zinc, or
zinc dialkyl dithio phosphate (ZDDP) can be a useful component of
the lubricating oils of this disclosure. ZDDP can be derived from
primary alcohols, secondary alcohols or mixtures thereof. ZDDP
compounds generally are of the formula
Zn[SP(S)(OR.sup.1)(OR.sup.2)].sub.2
where R.sup.1 and R.sup.2 are C.sub.1-C.sub.18 alkyl groups,
preferably C.sub.2-C.sub.12 alkyl groups. These alkyl groups may be
straight chain or branched. Alcohols used in the ZDDP can be
2-propanol, butanol, secondary to butanol, pentanols, hexanols such
as 4-methyl-2-pentanol, n-hexanol, n-octanol, 2-ethyl hexanol,
alkylated phenols, and the like. Mixtures of secondary alcohols or
of primary and secondary alcohol can be preferred. Alkyl aryl
groups may also be used.
[0168] Preferable zinc dithiophosphates which are commercially
available include secondary zinc dithiophosphates such as those
available from for example, The Lubrizol Corporation under the
trade designations "LZ 677A", "LZ 1095" and "LZ 1371", from for
example Chevron Oronite under the trade designation "OLOA 262" and
from for example Afton Chemical under the trade designation "HITEC
7169".
[0169] The ZDDP is typically used in amounts of from about 0.4
weight percent to about 1.2 weight percent, preferably from about
0.5 weight percent to about 1.0 weight percent, and more preferably
from about 0.6 weight percent to about 0.8 weight percent, based on
the total weight of the lubricating oil, although more or less can
often be used advantageously. Preferably, the ZDDP is a secondary
ZDDP and present in an amount of from about 0.6 to 1.0 weight
percent of the total weight of the lubricating oil.
[0170] Low phosphorus engine oil compositions are included in this
disclosure. For such compositions, the phosphorus content is
typically less than about 0.12 weight percent preferably less than
about 0.10 weight percent and most preferably less than about 0.085
weight percent, and in certain instances less than about 0.065
weight percent.
[0171] Other illustrative antiwear agents useful in this disclosure
include, for example, zinc alkyldithiophosphates, aryl phosphates
and phosphites, sulfur-containing esters, phosphosulfur compounds,
and metal or ash-free dithiocarbamates.
[0172] The antiwear additive concentration in the lubricating oils
of this disclosure can range from about 0.01 to about 5 weight
percent, preferably about 0.1 to 4.5 weight percent, and more
preferably from about 0.2 weight percent to about 4 weight percent,
based on the total weight of the lubricating oil.
Corrosion Inhibitors
[0173] The lubricating oil compositions include at least one
corrosion inhibitor. Corrosion inhibitors are used to reduce the
degradation of metallic parts that are in contact with the
lubricating oil composition. Suitable corrosion inhibitors include
aryl thiazines, alkyl substituted dimercaptothiodiazoles, alkyl
substituted dimercaptothiadiazoles, and mixtures thereof.
[0174] Corrosion inhibitors are additives that protect lubricated
metal surfaces against chemical attack by water or other
contaminants. A wide variety of these are commercially available.
As used herein, corrosion inhibitors include antirust additives and
metal deactivators.
[0175] One type of corrosion inhibitor is a polar compound that
wets the metal surface preferentially, protecting it with a film of
oil. Another type of corrosion inhibitor absorbs water by
incorporating it in a water-in-oil emulsion so that only the oil
touches the metal surface. Yet another type of corrosion inhibitor
chemically adheres to the metal to produce a non-reactive surface.
Examples of suitable additives include zinc dithiophosphates, metal
phenolates, basic metal sulfonates, fatty acids and amines. Such
additives may be used in an amount of about 0.01 to 5 weight
percent, preferably about 0.01 to 1.5 weight percent.
[0176] Illustrative corrosion inhibitors include (short-chain)
alkenyl succinic acids, partial esters thereof and
nitrogen-containing derivatives thereof; and synthetic
alkarylsulfonates, such as metal dinonylnaphthalene sulfonates.
Corrosion inhibitors include, for example, monocarboxylic acids
which have from 8 to 30 carbon atoms, alkyl or alkenyl succinates
or partial esters thereof, hydroxy-fatty acids which have from 12
to 30 carbon atoms and derivatives thereof, sarcosines which have
from 8 to 24 carbon atoms and derivatives thereof, amino acids and
derivatives thereof, naphthenic acid and derivatives thereof,
lanolin fatty acid, mercapto-fatty acids and paraffin oxides.
[0177] Particularly preferred corrosion inhibitors are indicated
below. Examples of monocarboxylic acids (C.sub.8-C.sub.30),
Caprylic acid, pelargonic acid, decanoic acid, undecanoic acid,
lauric acid, myristic acid, palmitic acid, stearic acid, arachic
acid, behenic acid, cerotic acid, montanic acid, melissic acid,
oleic acid, docosanic acid, erucic acid, eicosenic acid, beef
tallow fatty acid, soy bean fatty acid, coconut oil fatty acid,
linolic acid, linoleic acid, tall oil fatty acid, 12-hydroxystearic
acid, laurylsarcosinic acid, myritsylsarcosinic acid,
palmitylsarcosinic acid, stearylsarcosinic acid, oleylsarcosinic
acid, alkylated (C.sub.8-C.sub.20) phenoxyacetic acids, lanolin
fatty acid and C.sub.8-C.sub.24 mercapto-fatty acids.
[0178] Examples of polybasic carboxylic acids which function as
corrosion inhibitors include alkenyl (C.sub.10-C.sub.100) succinic
acids and ester derivatives thereof, dimer acid,
N-acyl-N-alkyloxyalkyl aspartic acid esters (U.S. Pat. No.
5,275,749). Examples of the alkylamines which function as corrosion
inhibitors or as reaction products with the above carboxylates to
give amides and the like are represented by primary amines such as
laurylamine, coconut-amine, n-tridecylamine, myristylamine,
n-pentadecylamine, palmitylamine, n-heptadecylamine, stearylamine,
n-nonadecylamine, n-eicosylamine, n-heneicosylamine,
n-docosylamine, n-tricosylamine, n-pentacosylamine, oleylamine,
beef tallow-amine, hydrogenated beef tallow-amine and soy
bean-amine. Examples of the secondary amines include dilaurylamine,
di-coconut-amine, di-n-tri decyl amine, dimyristylamine,
di-n-pentadecylamine, dipalmitylamine, di-n-pentadecylamine,
distearylamine, di-n-nonadecylamine, di-n-eicosylamine,
di-n-heneicosylamine, di-n-docosylamine, di-n-tricosylamine,
di-n-pentacosyl-amine, dioleylamine, di-beef tallow-amine,
di-hydrogenated beef tallow-amine and di-soy bean-amine. Examples
of the aforementioned N-alkylpolyalkyenediamines include:
ethylenediamines such as laurylethylenediamine, coconut
ethylenediamine, n-tridecylethylenediamine-,
myristylethylenediamine, n-pentadecylethylenediamine,
palmitylethylenediamine, n-heptadecylethylenediamine,
stearylethylenediamine, n-nonadecylethylenediamine,
n-eicosylethylenediamine, n-heneicosylethylenediamine,
n-docosylethylendiamine, n-tricosylethylenediamine,
n-pentacosylethylenediamine, oleylethylenediamine, beef
tallow-ethylenediamine, hydrogenated beef tallow-ethylenediamine
and soy bean-ethylenediamine; propylenediamines such as
laurylpropylenediamine, coconut propylenediamine,
n-tridecylpropylenediamine, myristylpropylenediamine,
n-pentadecylpropylenediamine, palmitylpropylenediamine,
n-heptadecylpropylenediamine, stearylpropylenediamine,
n-nonadecylpropylenediamine, n-eicosylpropylenediamine,
n-heneicosylpropylenediamine, n-docosylpropylendiamine,
n-tricosylpropylenediamine, n-pentacosylpropylenediamine,
diethylene triamine (DETA) or triethylene tetramine (TETA),
oleylpropylenediamine, beef tallow-propylenediamine, hydrogenated
beef tallow-propylenediamine and soy bean-propylenediamine;
butylenediamines such as laurylbutylenediamine, coconut
butylenediamine, n-tridecylbutylenediamine-myristylbutylenediamine,
n-pentadecylbutylenediamine, stearylbutylenediamine,
n-eicosylbutylenediamine, n-heneicosylbutylenedia-mine,
n-docosylbutylendiamine, n-tricosylbutylenediamine,
n-pentacosylbutylenediamine, oleylbutylenediamine, beef
tallow-butylenediamine, hydrogenated beef tallow-butylenediamine
and soy bean butylenediamine; and pentylenediamines such as
laurylpentylenediamine, coconut pentylenediamine,
myristylpentylenediamine, palmitylpentylenediamine,
stearylpentylenediamine, oleyl-pentylenediamine, beef
tallow-pentylenediamine, hydrogenated beef tallow-pentylenediamine
and soy bean pentylenediamine.
[0179] Other illustrative corrosion inhibitors include
2,5-dimercapto-1,3,4-thiadiazoles and derivatives thereof,
mercaptobenzothiazoles, alkyltriazoles and benzotriazoles. Examples
of dibasic acids useful as corrosion inhibitors, which may be used
in the present disclosure, are sebacic acid, adipic acid, azelaic
acid, dodecanedioic acid, 3-methyladipic acid, 3-nitrophthalic
acid, 1,10-decanedicarboxylic acid, and fumaric acid. The corrosion
inhibitors can be a straight or branch-chained, saturated or
unsaturated monocarboxylic acid or ester thereof which may
optionally be sulfurized in an amount up to 35% by weight.
Preferably the acid is a C.sub.4 to C.sub.22 straight chain
unsaturated monocarboxylic acid. The preferred concentration of
this additive is from 0.001% to 0.35% by weight of the total
lubricant composition. The preferred monocarboxylic acid is
sulfurized oleic acid. However, other suitable materials are oleic
acid itself; valeric acid and erucic acid. An illustrative
corrosion inhibitor includes a triazole as previously defined. The
triazole should be used at a concentration from 0.005% to 0.25% by
weight of the total composition. The preferred triazole is
tolylotriazole which may be included in the compositions of the
disclosure include triazoles, thiazoles and certain diamine
compounds which are useful as metal deactivators or metal
passivators. Examples include triazole, benzotriazole and
substituted benzotriazoles such as alkyl substituted derivatives.
The alkyl substituent generally contains up to 1.5 carbon atoms,
preferably up to 8 carbon atoms. The triazoles may contain other
substituents on the aromatic ring such as halogens, nitro, amino,
mercapto, etc. Examples of suitable compounds are benzotriazole and
the tolyltriazoles, ethylbenzotriazoles, hexylbenzotriazoles,
octylbenzotriazoles, chlorobenzotriazoles and nitrobenzotriazoles.
Benzotriazole and tolyltriazole are particularly preferred. A
straight or branched chain saturated or unsaturated monocarboxylic
acid which is optionally sulfurized in an amount which may be up to
35% by weight; or an ester of such an acid; and a triazole or alkyl
derivatives thereof, or short chain alkyl of up to 5 carbon atoms;
n is zero or an integer between 1 and 3 inclusive; and is hydrogen,
morpholino, alkyl, amido, amino, hydroxy or alkyl or aryl
substituted derivatives thereof; or a triazole selected from 1,2,4
triazole, 1,2,3 triazole, 5-anilo-1,2,3,4-thiatriazole,
3-amino-1,2,4 triazole, 1-H-benzotriazole-1-yl-methylisocyanide,
methylene-bis-benzotriazole and naphthotriazole.
[0180] The corrosion inhibitors may be used in an amount of 0.01 to
5 wt %, preferably 0.01 to 1.5 wt %, more preferably 0.01 to 0.2 wt
%, still more preferably 0.01 to 0.1 wt % (on an as-received basis)
based on the total weight of the lubricating oil composition.
Viscosity Modifiers
[0181] Viscosity modifiers (also known as viscosity index improvers
(VI improvers), and viscosity improvers) can be included in the
lubricant compositions of this disclosure.
[0182] Viscosity modifiers provide lubricants with high and low
temperature operability. These additives impart shear stability at
elevated temperatures and acceptable viscosity at low
temperatures.
[0183] Suitable viscosity modifiers include high molecular weight
hydrocarbons, polyesters and viscosity modifier dispersants that
function as both a viscosity modifier and a dispersant. Typical
molecular weights of these polymers are between about 10,000 to
1,500,000, more typically about 20,000 to 1,200,000, and even more
typically between about 50,000 and 1,000,000.
[0184] Examples of suitable viscosity modifiers are linear or
star-shaped polymers and copolymers of methacrylate, butadiene,
olefins, or alkylated styrenes. Polyisobutylene is a commonly used
viscosity modifier. Another suitable viscosity modifier is
polymethacrylate (copolymers of various chain length alkyl
methacrylates, for example), some compositions of which also serve
as pour point depressants. Other suitable viscosity modifiers
include copolymers of ethylene and propylene, hydrogenated block
copolymers of styrene and isoprene, and polyacrylates (copolymers
of various chain length acrylates, for example). Specific examples
include styrene-isoprene or styrene-butadiene based polymers of
50,000 to 200,000 molecular weight.
[0185] Olefin copolymers are commercially available from Chevron
Oronite Company LLC under the trade designation "PARATONE.RTM."
(such as "PARATONE.RTM. 8921" and "PARATONE.RTM. 8941"); from Afton
Chemical Corporation under the trade designation "HiTEC.RTM." (such
as "HiTEC.RTM. 5850B"; and from The Lubrizol Corporation under the
trade designation "Lubrizol.RTM. 7067C". Hydrogenated polyisoprene
star polymers are commercially available from Infineum
International Limited, e.g., under the trade designation "SV200"
and "SV600". Hydrogenated diene-styrene block copolymers are
commercially available from Infineum International Limited, e.g.,
under the trade designation "SV 50".
[0186] The polymethacrylate or polyacrylate polymers can be linear
polymers which are available from Evnoik Industries under the trade
designation "Viscoplex.RTM." (e.g., Viscoplex 6-954) or star
polymers which are available from Lubrizol Corporation under the
trade designation Asteric.TM. (e.g., Lubrizol 87708 and Lubrizol
87725).
[0187] Illustrative vinyl aromatic-containing polymers useful in
this disclosure may be derived predominantly from vinyl aromatic
hydrocarbon monomer. Illustrative vinyl aromatic-containing
copolymers useful in this disclosure may be represented by the
following general formula:
A-B
wherein A is a polymeric block derived predominantly from vinyl
aromatic hydrocarbon monomer, and B is a polymeric block derived
predominantly from conjugated diene monomer.
[0188] In an embodiment of this disclosure, the viscosity modifiers
may be used in an amount of less than about 10 weight percent,
preferably less than about 7 weight percent, more preferably less
than about 4 weight percent, and in certain instances, may be used
at less than 2 weight percent, preferably less than about 1 weight
percent, and more preferably less than about 0.5 weight percent,
based on the total weight of the lubricating oil composition.
Viscosity modifiers are typically added as concentrates, in large
amounts of diluent oil.
[0189] The viscosity modifiers may be used in an amount of 0 to 20
wt %, preferably 0.1 to 10 wt %, more preferably 0.5 to 7.5 wt %,
still more preferably 1 to 5 wt % (on an as-received basis) based
on the total weight of the lubricating oil composition.
[0190] As used herein, the viscosity modifier concentrations are
given on an "as delivered" basis. Typically, the active polymer is
delivered with a diluent oil. The "as delivered" viscosity modifier
typically contains from 20 weight percent to 75 weight percent of
an active polymer for polymethacrylate or polyacrylate polymers, or
from 8 weight percent to 20 weight percent of an active polymer for
olefin copolymers, hydrogenated polyisoprene star polymers, or
hydrogenated diene-styrene block copolymers, in the "as delivered"
polymer concentrate.
Metal Passivators
[0191] The lubricating oil compositions include at least one metal
passivator. The metal passivators/deactivators include, for
example, benzotriazole, tolyltriazole, 2-mercaptobenzothiazole,
dialkyl-2,5-dimercapto-1,3,4-thiadiazole;
N,N'-disalicylideneethylenediamine,
N,N'-disalicyli-denepropylenediamine; zinc dialkyldithiophosphates
and dialkyl dithiocarbamates.
[0192] Some embodiments of the disclosure may further comprise a
yellow metal passivator. As used herein, "yellow metal" refers to a
metallurgical grouping that includes brass and bronze alloys,
aluminum bronze, phosphor bronze, copper, copper nickel alloys, and
beryllium copper. Typical yellow metal passivators include, for
example, benzotriazole, totutriazole, tolyltriazole, mixtures of
sodium tolutriazole and tolyltriazole, and combinations thereof. In
one particular and non-limiting embodiment, a compound containing
tolyltriazole is selected. Typical commercial yellow metal
passivators include IRGAMET.TM.-30, and IRGAMET.TM.-42, available
from Ciba Specialty Chemicals, now part of BASE, and VANLUBE.TM.
601 and 704, and CUVAN.TM. 303 and 484, available from R.T.
Vanderbilt Company, Inc.
[0193] The metal passivator concentration in the lubricating oils
of this disclosure can range from about 0.01 to about 5.0 weight
percent, preferably about 0.01 to 3.0 weight percent, and more
preferably from about 0.01 weight percent to about 1.5 weight
percent, based on the total weight of the lubricating oil.
Other Additives
[0194] The lubricating oil useful in the present disclosure may
additionally contain one or more of the other commonly used
lubricating oil performance additives including but not limited to
polar agents, non-polar agents, ionic liquids, antistatic agents,
extreme pressure additives, anti-seizure agents, wax modifiers,
fluid-loss additives, seal compatibility agents, lubricity agents,
anti-staining agents, chromophoric agents, defoamants,
demulsifiers, emulsifiers, densifiers, wetting agents, gelling
agents, tackiness agents, colorants, lipids (hydrophilic,
lipophilic, amphiphilic), phospholipids, glycolipids,
glycerophospholipids, lecithin, and others.
[0195] Conductivity agents useful in the present disclosure
encompass materials, components, chemicals, or fluids having polar
functional groups, generally comprising heteroatoms, such as e.g.
O, N, P, S, B, halides, metals, and such polar functional groups
generally comprising e.g. esters, ethers, ketones, alcohols,
alkoxides, aldehydes, carboxylates, carboxylic acids, carboxylate
salts, sulfates, sulfones, sulfonates, sulfinates, heteroatom-metal
salts, amine salts, amines, amides, imides, imines,
hetero-aromatics, organometallics, and the like. Conductivity
agents encompass materials, components, chemicals, or fluids, that
increase the conductivity of a comparative fluid by a tangible
quantity, e.g. an increment of +100 pS/m or more, when added to
such comparative fluid in an effective amount. Conductivity agents
may be used individually, or two or more in combination, as
treatments or modifiers to compositions of lubricants and work
fluids.
[0196] An embodiment of this disclosure is the use of a polar
basestock, such as for example an ester, to control the dielectric
constant of a lubricating or working fluid composition, and
consequently to provide control over the value of the
conductivity-to-dielectric constant ratio. Such polar basestocks
and similarly acting agents are known as dielectric agents. An
additional embodiment is the combination of a dielectric agent,
such as for example a polar ester basestock, plus a conductivity
agent, such as for example a detergent, with such a combination
providing surprising control over obtaining desired performance
values of the conductivity-to-dielectric constant ratio. Polar
basestocks are typically classified as Group V basestocks, and
contain non-carbon heteroatoms such as, for example, O, N, S, P,
which impart polarity characteristics to the basestock. A
dielectric agent increases the dielectric constant of a lubricating
or working fluid composition by +0.02 units or more, when used at
an effective amount. Also, effective amounts of a dielectric agent
can increase the dielectric constant of a lubricating or working
fluid composition by 0.02 or more, by 0.04 or more, by 0.06 or
more, by 0.08 or more, by 0.1 or more, by 0.15 or more, and
sometimes 0.2 or more, depending on concentration. Conductivity
agents can function as dielectric agents, and similarly dielectric
agents can function as conductivity agents, depending on the
concentration of said agent in a lubricating or working fluid
composition, and depending on the contribution to the composition's
properties for conductivity or dielectric constant or both.
[0197] For a review of many commonly used additives, see Klamann in
Lubricants and Related Products, Verlag Chemie, Deerfield Beach,
Fla.; ISBN 0-89573-177-0. Reference is also made to "Lubricant
Additives" by M. W. Ranney, published by Noyes Data Corporation of
Parkridge, NJ (1973); see also U.S. Pat. No. 7,704,930, the
disclosure of which is incorporated herein in its entirety. These
additives are commonly delivered with varying amounts of diluent
oil, that may range from 5 weight percent to 50 weight percent.
[0198] The additives useful in this disclosure do not have to be
soluble in the lubricating oils. Insoluble additives such as zinc
stearate in oil can be dispersed in the lubricating oils of this
disclosure.
[0199] The types and quantities of performance additives used in
combination with the instant disclosure in lubricant compositions
are not limited by the examples shown herein as illustrations.
Ionic Liquids (ILs)
[0200] Ionic liquids are so-called salt melts which are preferably
liquid at room temperature and/or by definition have a melting
point <100.degree. C. They have almost no vapor pressure and
therefore have no cavitation properties. In addition, through the
choice of the cations and anions in the ionic liquids, the lifetime
and lubricating effect of the lubricating oil are increased, and by
adjusting the electric conductivity, these liquids can be used in
equipment in which there is an electric charge buildup, e.g.,
electric vehicle powertrains. Suitable cations for ionic liquids
include a quaternary ammonium cation, a phosphonium cation, an
imidazolium cation, a pyridinium cation, a pyrazolium cation, an
oxazolium cation, a pyrrolidinium cation, a piperidinium cation, a
thiazolium cation, a guanidinium cation, a morpholinium cation, a
trialkylsulfonium cation or a triazolium cation, which may be
substituted with an anion selected from the group consisting of
[PF.sub.6].sup.-, [BF.sub.4].sup.31, [CF.sub.3CO.sub.2].sup.31,
[CF.sub.3SO.sub.3].sup.-as well as its higher homologs,
[C.sub.4F.sub.9--SO.sub.3].sup.31 or
[C.sub.8F.sub.17--SO.sub.3].sup.- and higher
perfluoroalkylsulfonates, [(CF.sub.3SO.sub.2).sub.2N].sup.-,
[(CF.sub.3SO.sub.2)(CF.sub.3COO)N].sup.-,
[R.sup.1--SO.sub.3].sup.-, [R.sup.1--O--SO.sub.3].sup.31,
[R.sup.1--COO].sup.-, Cr.sup.-, Br.sup.-, [NO.sub.3].sup.-,
[N(CN).sub.2].sup.-, [HSO.sub.4].sup.-, PF.sub.(6-x)R.sup.3.sub.x
or [R.sup.1R.sup.2PO.sub.4].sup.- and the radicals R.sup.1 and
R.sup.2 independently of one another are selected from hydrogen;
linear or branched, saturated or unsaturated, aliphatic or
alicyclic alkyl groups with 1 to 20 carbon atoms; heteroaryl,
heteroaryl-C.sub.1-C.sub.6-alkyl groups with 3 to 8 carbon atoms in
the heteroaryl radical and at least one heteroatom of N, O and S,
which may be combined with at least one group selected from
C.sub.1-C.sub.6 alkyl groups and/or halogen atoms; aryl-aryl
C.sub.1-C.sub.6 alkyl groups with 5 to 12 carbon atoms in the aryl
radical, which may be substituted with at least one C.sub.1-C.sub.6
alkyl group; R.sup.3 may be a perfluoroethyl group or a higher
perfluoroalkyl group, x is 1 to 4. However, other combinations are
also possible.
[0201] Ionic liquids with highly fluorinated anions are especially
preferred because they usually have a high thermal stability. The
water uptake ability may be reduced significantly by such anions,
e.g., in the case of the bis(trifluoromethylsulfonyl)imide
anion.
[0202] Illustrative ionic liquids include, for example,
butylmethylpyrrolidinium bis(trifluoromethylsulfonyl)imide
(MBPimide), methylpropylpyrrolidinium
bis(trifluoromethylsulfonyl)imide (MPPimide),
hexylmethylimidazolium tris(perfluoroethyl)trifluorophosphate
(HMIMPFET), hexylmethylimidazolium
bis(trifluoromethylsulfonyl)imide (HMIMimide),
hexylmethylpyrrolidinium bis(trifluoromethylsulfonyl)imide (HMP),
tetrabutylphosphonium tris(perfluoroethyl)trifluorophosphate
(BuPPFET), octylmethylimidazolium hexafluorophosphate (OMIM PF6),
hexylpyridinium bis(trifluoromethyl)sulfonylimide (Hpyimide),
methyltrioctylammonium trifluoroacetate (MOAac),
butylmethylpyrrolidinium tris(pentafluoroethyl)trifluorophosphate
(MBPPFET), trihexyl(tetradecyl)phosphonium
bis(trifluoromethylsulfonyl)imide (HPDimide),
1-ethyl-3-methylimidazolium ethyl sulfate (EMIM ethyl sulfate),
1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide
(EMIMimide), 1-ethyl-2,3-dimethylimidazolium
bis(trifluoromethylsulfonyl)imide (EMMIMimide),
N-ethyl-3-methylpyridinium nonafluorobutanesulfonate (EMPyflate),
trihexyl(tetradecyl)phosphonium bis(trifluoromethylsulfonyl)amide,
trihexyl(tetradecyl)phosphonium
bis(2,4,4-trifluoromethylpentyl)phosphinate,
tributyl(tetradecyl)phosphonium dodecylbenzenesulfonate, and the
like.
[0203] Other illustrative ionic liquids include, for example,
1-ethyl-3-methylimidazolium dicyanamide,
trihexyltetradecylphosphonium bis(trifluoromethylsulfonyl)amide,
trihexyl(tetradecyl)phosphonium
bis(2,4,4-trimethylpentyl)phosphinate, 1-methyl-3-butylimidazolium
bis(trifluoromethanesulfonyl)imide, and tetradecylammonium
bis(2-ethylhexyl) phosphate.
[0204] Cation/anion combinations leading to ionic liquids include,
for example, dialkylimidazolium, pyridinium, ammonium and
phosphonium, etc. with organic anions such as sulfonates, imides,
methides, etc., as well as inorganic anions such as halides and
phosphates, etc., such that any other combination of cations and
anions with which a low melting point can be achieved is also
conceivable. Ionic liquids have an extremely low vapor pressure,
depending on their chemical structure, are nonflammable and often
have thermal stability up to more than 260.degree. C. and
furthermore are also suitable as lubricants.
[0205] The respective desired properties of the lubricant oil are
achieved with the ionic liquids through a suitable choice of
cations and anions. These desirable properties include adjusting
electrical conductivity of the lubricant to spread the area of use,
increasing the service life and lubricating effect of the
lubricant, and adjusting the viscosity to improve the temperature
suitability. Suitable cations for ionic liquids have proven to be a
phosphonium cation, an imidazolium cation, a pyridinium cation or a
pyrrolidinium cation which may be combined with an anion containing
fluorine and selected from bis(trifluoromethylsulfonyl)imide,
bis(perfluoroalkylsulfonyl)imide, perfluoroalkyl sulfonate,
tris(perfluoroalkyl)methidenes, bis(perfluoroalkyl)imidenes,
bis(perfluoroaryl)imides, perfluoroarylperfluoroalkylsulfonylimides
and tris(perfluoro-alkyl) trifluorophosphate or with a halogen-free
alkyl sulfate anion.
[0206] Ionic liquids useful in the present disclosure are those
that are soluble in hydrocarbon, hydrophobic-type, fluids (i.e.
oil-soluble), and soluble in suitable lubricating/working fluids.
Ionic liquids that are also useful in the present disclosure are
those that are soluble in polar, hydrophilic- or amphiphilic-type,
fluids (e.g. esters, ethers, etc.), and soluble in suitable
lubricating/working fluids. Further, ionic liquids useful in the
present disclosure may also be use in solid or semi-solid
lubricants such as e.g. greases.
[0207] In an embodiment, such ionic liquid additives may be used in
an amount of about 0.1 to 10 weight percent, preferably 0.5 to 7.5
weight percent, more preferably about 0.75 to 5 weight percent.
Antistatic Additives
[0208] In electric vehicle powertrains, static electricity is
generated, especially when the lubricant is in use. To reduce that
hazard, a conductive antistatic additive can be added to and
distributed throughout the lubricating oil. This lubricating oil
will thereby avoid reduction in its performance associated with
local breakdown of the base stock and safety problems from static
electric build-up.
[0209] A class of products called "antistatic fluids" or
"antistatic additives", which also are petroleum distillates, can
be added to adjust the conductivity of a lubricant oil to safe
levels, e.g., at or above 100 pico-siemens per meter conductivity.
Very small quantities of these antistatic fluids are required to
raise the conductivity to the desired levels, namely, some 10 to 30
milliliters per 1,000 gallons of hydrocarbon.
[0210] According to another feature of the disclosure, the
antistatic additive is selected from a population of commercially
available materials based on the ability of the material's chemical
compatibility with the lubricating oil and the cost effectiveness
of adjusting the conductivity of the lubricating oil to the desired
level for the lubricating oil's anticipated application.
[0211] Typical antistatic fluids are ExxonMobil.TM. Chemical's line
of de-aromatized hydrocarbon fluids known as Exxsol.TM. fluids.
Representative fluids and their distillation points include
Exxsol.TM. antistatic fluids hexane (65 IBP (.degree. C.) min, 71
DP (.degree. C.) max, and additive amount 30 ml/1000 gal), D 40
(150 IBP (.degree. C.) min, 210 DP (.degree. C.) max, and additive
amount 30 ml/1000 gal), D 3135 (152 IBP (.degree. C.) min, 182 DP
(.degree. C.) max, and additive amount 10 ml/1000 gal), and D 60
(177 IBP (.degree. C.) min, 220 DP (.degree. C.) max, and additive
amount 30 ml/1000 gal). The IBP is the temperature at which 1% of
the material is distilled, and the DP is the temperature at which
96% of the material is distilled.
[0212] Other illustrative antistatic agents are based on long-chain
aliphatic amines (optionally ethoxylated) and amides, quaternary
ammonium salts (e.g., behentrimonium chloride or cocamidopropyl
betaine), esters of phosphoric acid, polyethylene glycol esters, or
polyols. Additional antistatic agents include long-chain alkyl
phenols, ethoxylated amines, glycerol esters, such as glycerol
monostearate, amides, glycols, and fatty acids.
[0213] The quantity of antistatic additive required to adjust the
conductivity of the lubricating oil is determined by measuring the
conductivity of the lubricating oil as the antistatic additive is
mixed in and stopping when the desired conductivity consistent with
the application to be reached. The amount of antistatic additive
mixed in will range between 0.001% and 10% of the lubricating oil
by weight, and preferentially between 1% and 7.5% by weight, though
it may be mixed in at a liquid volume of between 10 and 100,000
parts per million.
Pour Point Depressants (PPDs)
[0214] Conventional pour point depressants (also known as lube oil
flow improvers) may be added to the lubricating oil compositions of
the present disclosure if desired. These pour point depressant may
be added to lubricating compositions of the present disclosure to
lower the minimum temperature at which the fluid will flow or can
be poured. Examples of suitable pour point depressants include
polymethacrylates, polyacrylates, polyarylamides, condensation
products of haloparaffin waxes and aromatic compounds, vinyl
carboxylate polymers, and terpolymers of dialkylfumarates, vinyl
esters of fatty acids and allyl vinyl ethers. U.S. Pat. Nos.
1,815,022; 2,015,748; 2,191,498; 2,387,501; 2,655, 479; 2,666,746;
2,721,877; 2,721,878; and 3,250,715 describe useful pour point
depressants and/or the preparation thereof. Such additives may be
used in an amount of about 0.01 to 5 weight percent, preferably 0.1
to 3 weight percent, more preferably about 0.5 to 1.5 weight
percent.
Seal Compatibility Agents
[0215] The lubricating oil compositions can include at least one
seas' compatibility agent. Seal compatibility agents help to swell
elastomeric seals by causing a chemical reaction in the fluid or
physical change in the elastomer. Suitable seal compatibility
agents for lubricating oils include organic phosphates, aromatic
esters, aromatic hydrocarbons, esters (butylbenzyl phthalate, for
example), and polybutenyl succinic anhydride. Such additives may be
used in an amount of about 0.01 to 5 weight percent, preferably 0.1
to 3 weight percent, more preferably about 0.5 to 1.5 weight
percent.
Antifoam Agents
[0216] Antifoam agents may advantageously be added to lubricant
compositions. These agents retard the formation of stable foams.
Silicones and organic polymers are typical antifoam agents. For
example, polysiloxanes, such as silicon oil or polydimethyl
siloxane, provide antifoam properties. Antifoam agents are
commercially available and may be used in conventional minor
amounts along with other additives such as demulsifiers; usually
the amount of these additives combined is less than 1 weight
percent and often less than 0.1 weight percent. In an embodiment,
such additives may be used in an amount of about 0.01 to 5 weight
percent, preferably 0.1 to 3 weight percent, more preferably about
0.5 to 1.5 weight percent.
Friction Modifiers
[0217] The lubricating oil compositions can include at least one
friction modifier. A friction modifier is any material or materials
that can alter the coefficient of friction of a surface lubricated
by any lubricant or fluid containing such material(s). Friction
modifiers, also known as friction reducers, or lubricity agents or
oiliness agents, and other such agents that change the ability of
base oils, lubricant compositions, or functional fluids, to modify
the coefficient of friction of a lubricated surface may be
effectively used in combination with the base oils or lubricant
compositions of the present disclosure if desired. Friction
modifiers that lower the coefficient of friction are particularly
advantageous in combination with the base oils and lube
compositions of this disclosure.
[0218] Illustrative friction modifiers may include, for example,
organometallic compounds or materials, or mixtures thereof.
Illustrative organometallic friction modifiers useful in the
lubricating engine oil compositions of this disclosure include, for
example, molybdenum amine, molybdenum diamine, an
organotungstenate, a molybdenum dithiocarbamate, molybdenum
dithiophosphates, molybdenum amine complexes, molybdenum
carboxylates, and the like, and mixtures thereof. Similar tungsten
based compounds may be preferable.
[0219] Other illustrative friction modifiers useful in the
lubricating engine oil compositions of this disclosure include, for
example, alkoxylated fatty acid esters, alkanolamides, polyol fatty
acid esters, borated glycerol fatty acid esters, fatty alcohol
ethers, and mixtures thereof.
[0220] Illustrative alkoxylated fatty acid esters include, for
example, polyoxyethylene stearate, fatty acid polyglycol ester, and
the like. These can include polyoxypropylene stearate,
polyoxybutylene stearate, polyoxyethylene isosterate,
polyoxypropylene isostearate, polyoxyethylene palmitate, and the
like.
[0221] Illustrative alkanolamides include, for example, lauric acid
diethylalkanolamide, palmic acid diethylalkanolamide, and the like.
These can include oleic acid diethyalkanolamide, to stearic acid
diethylalkanolamide, oleic acid diethylalkanolamide,
polyethoxylated hydrocarbylamides, polypropoxylated
hydrocarbylamides, and the like.
[0222] Illustrative polyol fatty acid esters include, for example,
glycerol mono-oleate, saturated mono-, di-, and tri-glyceride
esters, glycerol mono-stearate, and the like. These can include
polyol esters, hydroxyl-containing polyol esters, and the like.
[0223] Illustrative borated glycerol fatty acid esters include, for
example, borated glycerol mono-oleate, borated saturated mono-,
di-, and tri-glyceride esters, borated glycerol mono-sterate, and
the like. In addition to glycerol polyols, these can include
trimethylolpropane, pentaerythritol, sorbitan, and the like. These
esters can be polyol monocarboxylate esters, polyol dicarboxylate
esters, and on occasion polyoltricarboxylate esters. Preferred can
be the glycerol mono-oleates, glycerol dioleates, glycerol
trioleates, glycerol monostearates, glycerol distearates, and
glycerol tristearates and the corresponding glycerol
monopalmitates, glycerol dipalmitates, and glycerol tripalmitates,
and the respective isostearates, linoleates, and the like. On
occasion the glycerol esters can be preferred as well as mixtures
containing any of these. Ethoxylated, propoxylated, butoxylated
fatty acid esters of polyols, especially using glycerol as
underlying polyol can be preferred.
[0224] Illustrative fatty alcohol ethers include, for example,
stearyl ether, myristyl ether, and the like. Alcohols, including
those that have carbon numbers from C.sub.3 to C.sub.50, can be
ethoxylated, propoxylated, or butoxylated to form the corresponding
fatty alkyl ethers. The underlying alcohol portion can preferably
be stearyl, myristyl, C.sub.11-C.sub.13 hydrocarbon, oleyl,
isosteryl, and the like.
[0225] The lubricating oils of this disclosure exhibit desired
properties, e.g., wear control, in the presence or absence of a
friction modifier.
[0226] Useful concentrations of friction modifiers may range from
0.01 weight percent to 5 weight percent, or about 0.1 weight
percent to about 2.5 weight percent, or about 0.1 weight percent to
about 1.5 weight percent, or about 0.1 weight percent to about 1
weight percent. Concentrations of molybdenum-containing materials
are often described in terms of Mo metal concentration.
Advantageous concentrations of Mo may range from 25 ppm to 700 ppm
or more, and often with a preferred range of 50-200 ppm. Friction
modifiers of all types may be used alone or in mixtures with the
materials of this disclosure. Often mixtures of two or more
friction modifiers, or mixtures of friction modifier(s) with
alternate surface active material(s), are also desirable.
Extreme Pressure Agents
[0227] The lubricating oil compositions can include at least one
extreme pressure agent (EP). EP agents that are soluble in the oil
include sulfur- and chlorosulfur-containing EP agents, chlorinated
hydrocarbon EP agents and phosphorus EP agents. Examples of such EP
agents to include chlorinated wax; sulfurized olefins (such as
sulfurized isobutylene), organic sulphides and polysulphides such
as dibenzyldisulphide, bis-(chlorobenzyl)disulphide, dibutyl
tetrasulphide, sulfurized methyl ester of oleic acid, sulfurized
alkylphenol, sulfurized dipentene, sulfurized terpene, and
sulfurized Diels-Alder adducts; phosphosulfurized hydrocarbons such
as the reaction product of phosphorus sulphide with turpentine or
methyl oleate; phosphorus esters such as the dihydrocarbon and
trihydrocarbon phosphites, e.g., dibutyl phosphite, diheptyl
phosphite, dicyclohexyl phosphite, pentylphenyl phosphite;
dipentylphenyl phosphite, tridecyl phosphite, distearyl phosphite
and polypropylene substituted phenol phosphite; metal
thiocarbamates such as zinc dioctyldithio carbamate and barium
heptylphenol diacid; amine salts of alkyl and dialkylphosphoric
acids or derivatives; and mixtures thereof (as described in U.S.
Pat. No. 3,197,405).
[0228] The extreme pressure agents may be used in an amount of 0.01
to 5 wt %, preferably 0.01 to 1.5 wt %, more preferably 0.01 to 0.2
wt %, still more preferably 0.01 to 0.1 wt % (on an as-received
basis) based on the total weight of the lubricating oil
composition.
[0229] When lubricating oil compositions contain one or more of the
additives discussed above, the additive(s) are blended into the
composition in an amount sufficient for it to perform its intended
function. Typical amounts of such additives useful in the present
disclosure are shown in Table 1 below.
[0230] It is noted that many of the additives are shipped from the
additive manufacturer as a concentrate, containing one or more
additives together, with a certain amount of base oil diluents.
Accordingly, the weight amounts in the table below, as well as
other amounts mentioned herein, are directed to the amount of
active ingredient (that is the non-diluent portion of the
ingredient). The weight percent (wt %) indicated below is based on
the total weight of the lubricating oil composition.
TABLE-US-00002 TABLE 1 Typical Amounts of Lubricating Oil
Components Approximate Approximate Compound wt % (Useful) wt %
(Preferred) Antioxidant 0.01-5 .sup. 0.1-1.5 Dispersant
0.01-20.sup. 0.1-10 Detergent 0.01-10.sup. .sup. 0.1-7.5 Antiwear
0.01-5 0.5-4 Viscosity Modifier (solid 0-20 0.1-10 polymer basis)
Corrosion Inhibitor 0.01-5 0.1-2 Metal Passivator 0.01-5 .sup.
0.1-1.5 Friction Modifier 0-5 .sup. 0.1-1.5 Pour Point Depressant
0-5 0.01-1.5 Antifoam Agent 0-3 0.001-0.15 Extreme Pressure Agent
0-5 0.01-2 Anti-Static 0-10 0.1-5 Ionic Liquid 0-10 0.1-5
[0231] These additives may be added independently but are usually
precombined in packages which can be obtained from suppliers of
lubricant oil additives. Additive packages with a variety of
ingredients, proportions and characteristics are available and
selection of the appropriate package will take the requisite use of
the ultimate composition into account.
[0232] The following non-limiting examples are provided to
illustrate the disclosure.
Examples
[0233] Lubricating oil compositions were prepared as described
herein.
[0234] The additive packages used in the comparative compositions
(Table 2) include one or more additives in effective amounts.
Additives used in the compositions were one or more of an
antioxidant, dispersant, detergent, antiwear agent, corrosion
inhibitor, viscosity modifier, and metal passivator. Optional
additives were one or more of a pour point depressant, metal
deactivator, seal compatibility additive, antifoam agent, extreme
pressure agent, and friction modifier. For the inventive examples
disclosed herein, the inventive example compositions use the
additive package identified by the comparative oil listed in the
respective tables, with the appropriate comparative oil composition
as recited in Table 2.
TABLE-US-00003 TABLE 2 Comparative Oils; Compositions &
Properties Comparative Comparative Comparative Comparative
Comparative Comparative Comparative 3 4 5 6 7 8 9 Composition (Wt
%) Basestocks Group II 40 40 40 Group III 39 21 40 40 40 Group IV
60 77 5 94 36 Group V 10 10 10 5 5 Additive Package 11 9 23 10 15 1
19 Properties Ratio 286 749 1980 27 628 1.5 8222 Conductivity/
Dielectric Constant Conductivity, pS/m 694 1850 4910 62 1463 3.4
19240 Dielectric Constant 2.43 2.18 2.48 2.32 2.33 2.20 2.34
Viscosity, KV100 4.88 5.39 6.24 4.82 5.34 4.06 10.76 Viscosity,
KV40 16.85 29.48 16.77 23.75 57.22
[0235] Lubricating oils for electric vehicle powertrains were
prepared by blending at least one lubricating oil base stock
selected from a Group I, Group II, Group III, Group IV, Group V
base oil, and combinations thereof, with one or more lubricating
oil additives selected from an antioxidant, a detergent, a
dispersant, an antiwear additive, a corrosion inhibitor, a
viscosity modifier, a metal passivator, a pour point depressant, a
metal deactivator, a seal compatibility additive, an antifoam
agent, an extreme pressure agent, a friction modifier, other
performance additives, and combinations thereof.
[0236] Conductivity agents included in these examples are listed in
Table A.
TABLE-US-00004 TABLE A Conductivity Agents Conductivity Agents
Class Description IL-1 Ionic Liquid (IL)
1-Ethyl-3-methylimidazolium dicyanamide IL-2 Ionic Liquid (IL)
Trihexyltetradecylphosphonium bis(trifluoromethylsulfonyl)amide
IL-3 Ionic Liquid (IL) Trihexyl(tetradecyl)phosphonium
bis(2,4,4-trimethylpentyl)phosphinate IL-4 Ionic Liquid (IL)
Tributyl(tetradecyl)phosphonium dodecylbenzenesulfonate IL-5 Ionic
Liquid (IL) 1-Methyl-3-butylimidazolium bis
(trifluoromethanesulfonyl)imide IL-6 Ionic Liquid (IL)
Tetradecylammonium bis(2-ethylhexyl) phosphate PL-1 phospholipid
(PL) L-.alpha.-Phosphatidylcholine PL-2 phospholipid (PL) Lecithin
FA-1 fatty acid (FA) Stearic Acid Disp-1 Dispersant (Disp) Alkyl
Succinimide (nominal MW 4000) Disp-2 Dispersant (Disp)
Zinc-modified alkyl succinimide Disp-3 Dispersant (Disp) Alkyl
Succinimide (nominal MW 5000) Disp-4 Dispersant (Disp) Borated
alkyl succinimide (nominal MW 3000) Det-1 Detergent (Det) Ca alkyl
salicylate (low base) Det-2 Detergent (Det) Ca alkyl salicylate
(mixed bases) Det-3 Detergent (Det) Ca sulfonate (neutral) ZDDP-1
Antiwear Zinc dialkyl dithiophosphate Ester-1 Ester fluid
Diethylhexyl azelate
[0237] Electrical conductivity increases to low-conductivity oil
are demonstrated in Table 3, where conductivity agents such as
ionic liquids (IL-1, IL-3, IL-5, IL-6), phospholipids (PL-1, PL-2),
and fatty acid (FA-1), are added to low-conductivity oil
Comparative 3. Increases in conductivity of greater than +100 pS/m
were obtained in all Examples 3.1 to 3.10. Further, Examples 3.1 to
3.8 have ratios of conductivity-to-dielectric constant of less than
1,000, and thus have performances with improved protection against
battery charge drainage. Examples 3.9 and 3.10 demonstrate use of
conductivity agents (IL-3, PL-2) at higher dose concentrations
(about +0.3% or above in these cases) to achieve high
conductivities in the performance space where the ratio of
conductivity-to-dielectric constant is equal to or greater than
1,000, and thus have performances with improved protection against
bearing electrical discharge.
TABLE-US-00005 TABLE 3 Effect of Conductivity Agents on Oils with
Conductivity-to-Dielectric Constant Ratio >200 Comparative
Example Example Example Example Example Example Example Example
Example Example 3 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 3.10
Composition (Wt %) Comparative 3 100 99.9 99.95 99.9 99.95 99.95
99.95 99.95 99.95 99.5 99.5 Conductivity Agents IL-1 0.1 IL-3 0.05
0.1 0.5 IL-5 0.05 IL-6 0.05 PL-1 0.05 PL-2 0.05 0.5 FA-1 0.05
Properties Ratio 286 708 385 479 662 376 644 528 595 1847 2286
Conductivity/ Dielectric Constant Conductivity, 694 1650 900 1120
1550 880 1500 1230 1380 4360 5350 pS/m Dielectric 2.43 2.33 2.34
2.34 2.34 2.34 2.33 2.33 2.32 2.36 2.34 Constant
[0238] Electrical conductivity increases to moderate-conductivity
oil are demonstrated in Table 4, where conductivity agents such as
ionic liquids (IL-1, IL-3), and phospholipid (PL-2), were added to
moderate-conductivity oil Comparative 4. Increases in conductivity
of greater than +100 pS/m were achieved in Examples 4.1, 4.3, 4.4,
and 4.5. Example 4.2 illustrates that IL-3 requires a dose of
greater than about +0.1% to achieve the desired +100 pS/m increase
versus Comparative 4. Examples 4.1 to 4.3 have ratios of
conductivity-to-dielectric constant of less than 1,000, and thus
have performances with improved protection against battery charge
drainage. Examples 4.4 and 4.5 demonstrate use of conductivity
agents (IL-3, PL-2) at higher dose concentrations to obtain ratios
of conductivity-to-dielectric constant equal to or greater than
1,000, and thus have performances with improved protection against
bearing electrical discharge.
TABLE-US-00006 TABLE 4 Effect of Conductivity Agents on Oils with
Conductivity-to-Dielectric Constant Ratio >700 Comparative
Example Example Example Example Example 4 4.1 4.2 4.3 4.4 4.5
Composition (Wt %) Comparative 4 100 99.9 99.9 99.95 99.5 99.5
Conductivity Agents IL-1 0.1 IL-3 0.1 0.5 PL-2 0.05 0.5 Properties
Ratio 749 954 854 959 1204 2023 Conductivity/Dielectric Constant
Conductivity, pS/m 1850 2090 1870 2100 2660 4450 Dielectric
Constant 2.18 2.19 2.19 2.19 2.21 2.20
[0239] Electrical conductivity increases to higher-conductivity oil
are demonstrated in Table 5, where conductivity agents such as
ionic liquids (IL-1, IL-2, IL-3, IL-4), and phospholipid (PL-2),
were added to higher-conductivity oil Comparative 5. Increases in
conductivity of greater than +100 pS/m were achieved in Examples
5.1 to 5.7, and 5.9. Example 5.8 illustrates that PL-2 requires a
dose of greater than about +0.05% to achieve the desired +100 pS/m
increase versus Comparative 5. All Examples 5.1 to 5.9 demonstrate
use of conductivity agents to obtain conductivities where the ratio
of conductivity-to-dielectric constant is equal to or greater than
1,000, and thus have performances with improved protection against
bearing electrical discharge.
TABLE-US-00007 TABLE 5 Effect of Conductivity Agents on Oils with
Conductivity-to-Dielectric Constant Ratio >1900 Comparative
Example Example Example Example Example Example Example Example
Example 5 5.1 5.2 5.3 5.4 5.5 5.6 5.7 5.8 5.9 Composition (Wt %)
Comparative 5 100 99.9 99.5 99 99.9 99.9 99.5 99.9 99.95 99.5
Conductivity Agents IL-1 0.1 0.5 1 IL-2 0.1 IL-3 0.1 0.5 IL-4 0.1
PL-2 0.05 0.5 Properties Ratio 1980 3310 3747 4117 2980 2844 3571
4064 1943 2810 Conductivity/Dielectric Constant Conductivity, pS/m
4910 8210 9330 10210 7420 7110 8820 10160 4800 6940 Dielectric
Constant 2.48 2.48 2.49 2.48 2.49 2.50 2.47 2.50 2.47 2.47
[0240] Table 6 illustrates that a selected dispersant, in
combination with one or more performance additives, or in
combination with a selected performance additive package, increases
the conductivity of a typical lubricating or working fluid. Example
6.2 illustrates that dispersant Disp-2 gives a surprisingly large
increase in the conductivity of a low-conductivity oil Comparative
6, and obtains a ratio of conductivity-to-dielectric constant of
about 721, i.e. less than about 1000, and thus has performance for
improved protection against battery charge drainage. Use of Disp-2
at a higher concentration in a suitable finished lubricating or
working fluid results in ratios of conductivity-to-dielectric
constant equal to or greater than 1,000 and thus has performance
with improved protection against bearing electrical discharge.
TABLE-US-00008 TABLE 6 Effect of Dispersants as Conductivity Agents
Compar- Exam- Exam- Exam- ative 6 ple 6.1 ple 6.2 ple 6.3
Composition (Wt %) Comparative 6 100 99 98.5 99.3 Conductivity
Agents Disp-1 1.0 Disp-2 1.5 Disp-3 0.7 Properties Ratio 27 286 721
259 Conductivity/Dielectric Constant Conductivity, pS/m 62 694 1751
626 Dielectric Constant 2.32 2.43 2.43 2.42 Viscosity, KV100 4.82
4.88 4.91 4.87 Viscosity, KV40 16.8 16.8 17.2 16.8
[0241] Electrical conductivity versus time, in a test of service
life under oxidation conditions, of lubricant Examples 6.1, 6.2,
and 6.3, plus a comparative transmission fluid, Comparative 7, are
listed in Table 7. Oils were oxidized using a modified version of
the ASTM D4310 test, where temperature was maintained at 125 C, and
test oil was sampled at periodic intervals to measure acidity and
conductivity. Typical transmission fluid Comparative 7 performed
poorly with loss of control over electrical conductivity,
demonstrating a conductivity of 25,000 pS/m after 984 hours
time-on-test, i.e a conductivity increase of greater than 15-fold
versus that of fresh fluid. In contrast to the comparative
transmission fluid Comparative 7, lubricant Examples 6.1, 6.2, and
6.3 showed electrical conductivity control within the range of less
than about 6,000 pS/m over about 984 hours time-on-test, i.e. a
conductivity increase of about 2-fold to 5-fold increase versus
fresh oil. Electrical conductivity control is important for
maintaining battery and oil life.
TABLE-US-00009 TABLE 7 Oxidation Performance of Oils with
Dispersant Conductivity Agents Oxidation Life Comparative 7 Example
6.1 Example 6.2 Example 6.3 Time, hrs 0 984 1134 0 984 1134 0 984
1134 0 984 1134 Ratio 628 10504 3193 286 1664 1578 721 2259 1599
259 1012 968 Conductivity/Dielectric Constant Conductivity, pS/m
1463 25000 7760 694 4110 3930 1751 5580 3980 626 2500 2400
Dielectric Constant 2.33 2.38 2.43 2.43 2.47 2.49 2.43 2.47 2.49
2.42 2.47 2.48 Viscosity (cP), 25 C. 35.5 43.4 66.81 24.2 31.0 43.5
25.8 31.7 32.94 24.6 35.5 33.06 TAN 1.51 3.03 5.90 0.43 0.78 0.56
0.70 0.77 0.72 0.51 1.04 1.19 Copper, ppm 0 >68 0 39 0 >62 0
41
[0242] Further regarding Table 7, oxidation of both the comparative
and example oils beyond 984 hours to an extended time of 1134 hours
demonstrate decreases in oxidized oil conductivity. These
unexpected results are attributed to a process where soluble
high-conductivity materials, derived from oxidation, are removed
from solution by deposition, thereby lowering the conductivity of
the resulting oil compositions. Therefore, such a system of
monitoring the conductivity, and other electrical properties, of
lubricants and working fluids under oxidizing conditions
constitutes a novel sensor system for detecting the relative
cleanliness of such fluids in service and for detecting the
deposition of insoluble materials onto available surfaces within
the service or mechanical environment.
[0243] Referring to Table 7, Examples 6.1, 6.2, and 6.3 have
compositions in accordance with Table 1 above. Comparative 7
transmission fluid is a typical automatic transmission fluid.
[0244] Other performance attributes of the electric vehicle
powertrain lubricating oils during service life are also
illustrated in Table 7. Fluid acidity, as measured by TAN
influences electrical conductivity. As oils degrade, TAN increases,
and such increases contribute to electrical conductivity increases.
Electrical conductivity control is important to decrease the
chances of battery drain and electrical breakdown.
[0245] Total acid number (TAN) over time in a test of service life
under oxidation conditions, of lubricant Examples 6.1, 6.2, and
6.3, plus a comparative transmission fluid, Comparative 7, is
listed in Table 7. Examples 6.1, 6.2, and 6.3 demonstrated good
control over TAN, all lower than about 1.2 after 984 hours
time-on-test. The comparative transmission fluid, Comparative 7,
demonstrated a TAN of about 3.0 after 984 hours time-on-test, which
is a typical condemning limit for lubricating oils.
[0246] The effect of other additives on the electrical properties
of lubricant compositions are listed in Table 8a, and illustrate
the effects of borated dispersant (Disp-4, Example 8.1), salicylate
detergents (Det-1 and Det-2, Examples 8.2 and 8.3), sulfonate
detergent (Det-3, Examples 8.4 and 8.5), and a combination of
sulfonate detergent and ZDDP antiwear (Det-3 & ZDDP-1, Example
8.6). The use of a polar fluid such as ester base stock (Examples
8.7 and 8.8) illustrates the specific control over the dielectric
constant of the lubricant composition, and thus provides additional
control over the ratio of conductivity-to-dielectric constant as
recited in this disclosure. Further, combinations of polar
basestocks and other conductivity agents give additional control in
order to obtain targeted, desirable ratios of
conductivity-to-dielectric constant. Among these examples of Table
8a, Examples 8.1, 8.2, 8.4, 8.7, and 8.8 have ratios of
conductivity-to-dielectric constant of less that about 1,000, thus
have performances with improved protection against battery charge
drainage. Examples 8.3, 8.5, and 8.6 have ratios of
conductivity-to-dielectric constant equal to or greater than about
1,000, and thus have performances with improved protection against
bearing electrical discharge. Additional illustrative examples are
listed in Table 8b.
TABLE-US-00010 TABLE 8a Effect of Additives as Conductivity Agents
Comparative Example Example Example Example Example Example Example
Example 8 8.1 8.2 8.3 8.4 8.5 8.6 8.7 8.8 Composition (Wt %)
Comparative 8 100 99 99 99 99 96 96 75 45 Conductivity Agents
Disp-4 1 Det-1 1 Det-2 1 Det-3 1 4 3 ZDDP-1 1 Ester-1 25 55
Properties Ratio 1.5 583 120 1795 633 1716 3593 7.3 45
Conductivity/ Dielectric Constant Conductivity, pS/m 3.4 1282 265
3950 1399 3810 7940 19 145 Dielectric Constant 2.20 2.20 2.21 2.20
2.21 2.22 2.21 2.62 3.21 Viscosity, KV100 4.06 4.18 4.09 4.10 4.12
4.31 4.25 3.66 3.33
TABLE-US-00011 TABLE 8b Illustrative Examples of Conductivity
Agents Comparative Example Example Example Example Example Example
8 8.9 8.10 8.11 8.12 8.13 8.14 Composition (Wt %) Comparative 8 100
74 98 83 74 81 98 Conductivity Agents Disp-4 1 1 1 Det-1 1 1 Det-2
1 1 Det-3 3 ZDDP-1 1 1 Ester-1 25 15 25 15 Properties Illustrative
Ratio 1.5 <1000 <1000 <1000 >1000 >1000 >1000
Conductivity/Dielectric Constant
[0247] Table 9 lists lubricant compositions where conductivity
agents were useful in modifying ratios of
conductivity-to-dielectric constant where such ratios were high,
and in these examples, were greater than about 8,000. Ionic
liquids, IL-3 and IL-4, can be effectively used as conductivity
agents over a range of concentrations of about 0.01% to 1%, and
achieve ratios of conductivity-to-dielectric constant of from about
8,340 up to about 26,440 (Examples 9.1 to 9.4). These examples
(Table 9) have ratios of conductivity-to-dielectric constant equal
to or greater than about 1,000, and thus have performances with
improved protection against bearing electrical discharge.
TABLE-US-00012 TABLE 9 Effect of Conductivity Agents on Oils with
Conductivity-to-Dielectric Constant Ratio >8000 Comparative 9
Example 9.1 Example 9.2 Example 9.3 Example 9.4 Composition (Wt %)
Comparative 9 100 99.99 99 99.99 99 Conductivity Agents IL-3 0.01 1
IL-4 0.01 1 Properties Ratio 8222 8983 17016 8323 26413
Conductivity/Dielectric Constant Conductivity, pS/m 19240 21020
42200 19560 65240 Dielectric Constant 2.34 2.34 2.48 2.35 2.47
Viscosity, KV100 10.76 Viscosity, KV40 57.22
[0248] In an embodiment, compatibility of the lubricating oils of
this disclosure with an energized electrical or electronic
component can be determined in accordance with the method disclosed
in U.S. Application Publication No. 2015/0355122, herein
incorporated by reference for such method. In particular, the
method involves (a) contacting a test apparatus with lubricating
oil; (b) applying an electrical current to the test apparatus; and
(c) monitoring the current flow through the test apparatus over
time. The test apparatus includes at least one pair of conductors
separated by an insulator that does not extend across the whole of
the opposing surfaces of the conductors. The electrical current is
applied across the pair of conductors.
PCT and EP Clauses:
[0249] 1. A method for improving electrical performance in an
electric vehicle powertrain by reducing electrical charge drainage
of electrical energy storage devices and extending useful device
lifetime, said method comprising providing to an electric vehicle
powertrain a lubricating oil having a composition comprising: a
lubricating base oil as a major component; an additive package, as
a minor component comprising one or more lubricating oil additives;
and an effective amount of one or more conductivity agents, as a
minor component; wherein the lubricating oil has an electrical
conductivity from 10 pS/m to 20,000 pS/m, a dielectric constant of
1.6 to 3.6, and a ratio of electrical conductivity-to-dielectric
constant from 5 to less than 1,000.
[0250] 2. The method of clause 1 wherein the lubricating oil has a
kinematic viscosity from about 2 cSt to about 20 cSt at 100.degree.
C., a total acid number (TAN) less than about 3, less than about
200 ppm active sulfur, and a viscosity index (VI) greater than
about 50.
[0251] 3. The method of clauses 1-2 wherein the lubricating oil
comprises at least about 70 weight percent of a lubricating base
oil.
[0252] 4. The method of clauses 1-3 wherein the lubricating oil
comprises from about 0.01 to about 30 weight percent of the
additive package.
[0253] 5. The method of clauses 1-4 wherein the additive package
comprises one or more lubricating oil additives selected from the
group consisting of an antioxidant, a detergent, a dispersant, an
antiwear agent, a corrosion inhibitor, a viscosity modifier, a
metal passivator, a pour point depressant, a seal compatibility
agent, an antifoam agent, an extreme pressure agent, a friction
modifier, and mixtures thereof; and from about 0.01 to about 30
weight percent of a conductivity agent.
[0254] 6. The method of clauses 1-5 wherein the lubricating base
oil comprises: a blend of a Group IV base stock and a Group V base
stock; a blend of a Group III base stock and a Group V base stock;
a blend of a Group II base stock and a Group V base stock; or a
blend of a Group I base stock and a Group V base stock.
[0255] 7. The method of clauses 1-6 wherein the one or more
conductivity agents are selected from the group consisting of ionic
liquids, phospholipids, fatty acids, dispersants, detergents,
antiwear agents, polar basestock fluids, and mixtures thereof.
[0256] 8. The method of clauses 1-7 further including a dielectric
agent.
[0257] 9. The method of clauses 1-8 wherein the electric vehicle
powertrain is one or more of an electric motor, an electric drive
motor, a transmission, a front axle, a rear axle, a gear box, a
differential, gears, bearings, a battery, a capacitor, a generator,
an alternator, a converter, a kinetic energy accumulator, or a
kinetic energy recovery system.
[0258] 10. The method of clauses 1-9 wherein the electrical
conductivity is maintained at about to 10 pS/m to about 20,000 pS/m
over the lifetime of the lubricating oil.
[0259] 11. The method of clauses 1-10 wherein two or more of the
lubricating oils are used in the electric vehicle powertrain, and
wherein the two or more lubricating oils are different.
[0260] 12. A method for controlling electrical conductivity over a
lifetime of a lubricating oil in an electric vehicle powertrain
lubricated with the lubricating oil, comprising providing to an
electric vehicle powertrain a lubricating oil having a composition
comprising: a lubricating base oil as a major component; an
additive package, as a minor component comprising one or more
lubricating oil additives; and an effective amount of one or more
conductivity agents, as a minor component; wherein the lubricating
oil has an electrical conductivity from 10 pS/m to 20,000 pS/m, a
dielectric constant of 1.6 to 3.6, with a ratio of electrical
conductivity-to-dielectric constant from 5 to less than 1,000.
[0261] 13. A method for lubricating an electric vehicle powertrain
in an electric vehicle by reducing electrical charge drainage of
electrical energy storage devices and extending useful device
lifetime, said method comprising providing to an electric vehicle
powertrain a lubricating oil having a composition comprising: a
lubricating base oil as a major component; an additive package, as
a minor component comprising one or more lubricating oil additives;
and an effective amount of one or more conductivity agents, as a
minor component; wherein the lubricating oil has an electrical
conductivity from 10 pS/m to 20,000 pS/m, a dielectric constant of
1.6 to 3.6, with a ratio of electrical conductivity-to-dielectric
constant from 5 to less than 1,000.
[0262] 14. A method for obtaining a desired electrical
conductivity-to-dielectric constant ratio of a lubricating oil for
an electric vehicle powertrain, said method comprising: selecting
at least one lubricating base oil as a major component; selecting
at least one additive package as a minor component, comprising one
or more lubricating oil additives; and selecting at least one
conductivity agent as a minor component; and blending the selected
at least one lubricating oil base stock, the selected at least one
additive package, and an effective amount of the selected at least
one conductivity agent, to obtain a desired electrical
conductivity-to-dielectric constant ratio of the lubricating oil;
wherein the lubricating oil has an electrical conductivity from 10
pS/m to 20,000 pS/m, a dielectric constant of 1.6 to 3.6, with a
ratio of electrical conductivity-to-dielectric constant from 5 to
less than 1,000.
[0263] All patents and patent applications, test procedures (such
as ASTM methods, UL methods, and the like), and other documents
cited herein are fully incorporated by reference to the extent such
disclosure is not inconsistent with this disclosure and for all
jurisdictions in which such incorporation is permitted.
[0264] When numerical lower limits and numerical upper limits are
listed herein, ranges from any lower limit to any upper limit are
contemplated. While the illustrative embodiments of the disclosure
have been described with particularity, it will be understood that
various other modifications will be apparent to and can be readily
made by those skilled in the art without departing from the spirit
and scope of the disclosure. Accordingly, it is not intended that
the scope of the claims appended hereto be limited to the examples
and descriptions set forth herein but rather that the claims be
construed as encompassing all the features of patentable novelty
which reside in the present disclosure, including all features
which would be treated as equivalents thereof by those skilled in
the art to which the disclosure pertains.
[0265] The present disclosure has been described above with
reference to numerous embodiments and specific examples. Many
variations will suggest themselves to those skilled in this art in
light of the above detailed description. All such obvious
variations are within the full intended scope of the appended
claims.
* * * * *
References